The recently announced reciprocal green lane agreement between Singapore and Malaysia is a small but significant step forward, not just bilaterally but also in the broader context of how countries in South-east Asia can safely reopen their borders amid an ongoing pandemic.

Set to begin on Aug 10, it could be the precursor to an eventual Asean-wide "travel bubble". More immediately, it offers an important first test case of how countries can successfully lift restrictions bit by bit while keeping the spread of the coronavirus in check.

The Singapore-Malaysia green lane is, as the name suggests, a lane, not a highway. It limits cross-border travel to long-term pass holders and travellers on essential or official business.

There are also restrictions under the accompanying periodic commuting arrangement.

For instance, those allowed to travel under this arrangement must remain in their country of work for at least three consecutive months before being allowed to return home for short-term leave.

Health protocols and other procedural details are still being worked out and will be published only 10 days before the implementation date.

In short, the rules of the road, as it were, are still being worked out and will likely need to be adjusted along the way as these are put to the test in real life.

As things improve and greater confidence is gained, the hope is that other Asean member states can learn from it, adopt it and adapt it, and in time, smaller bilateral travel bubbles in the region will coalesce finally into an Asean one.

For that to happen, a number of things need to happen.

COMMON RULES AND STANDARDS

First, greater harmonisation of standards is needed.

The Singapore-Malaysia agreement has taken a step in that direction by mandating that travellers will need to abide strictly by "Covid-19 prevention and public health measures mutually agreed upon by both countries".

Beyond the regulatory harmonisation, there will also need to be downstream mutual recognition of testing, laboratory and epidemiologic surveillance standards.

The experience after the agreement goes "live" on Aug 10 will provide practical knowledge on how that works out and will be useful for other Asean members planning similar bilateral arrangements.

In a similar vein, all members of a region-wide travel bubble should strive to avoid duplication and confusion for travellers by agreeing on a common standard for essentials such as health declaration forms and movement tracking apps.

Second, Asean as a supra-national entity must take greater leadership in building the infrastructure and institutions in order to lay the foundations for a South-east Asian "safe travel zone".

For starters, common rules need to be established and enforced.

Provisions must also be made for unforeseen changes in circumstances and unexpected scenarios given the volatile nature of the pandemic. A way must be found to resolve disputes, such as over border controls, should the existing guidelines prove to be inadequate. Asean's founding principle of non-interference will likely be sorely tested if there is no binding means of decision-making.

AN ASEAN CDC

We believe an Asean Centre for Disease Control and Prevention (CDC) will be a useful component in efforts to set up a regional travel bubble. Just as the European Medicines Agency determines regulations for pharmaceuticals across the European Union and is binding on members, so an Asean CDC can independently set out public health policies for regional travel, coordinate testing standards and laboratory standards and conduct multi-country surveillance.

It can also play the role of "neutral arbiter", one that is critical as countries understandably have national interests to protect in the event of disputes. Along with the Asean CDC, there should be a mechanism to resolve differences and avoid full-scale withdrawal from the regional travel bubble.

Third, we recommend a formal fortnightly review process, similar to the EU model, to be built into the regional travel framework given the fluid nature of Covid-19.

RULES-BASED EXITS

It is best if all are agreed on an objective, measurable trigger for a country's temporary exclusion from the bubble so that decisions can be taken quickly and apolitically.

These "temporary exclusions" from travel bubble arrangements should be built into the legal instruments signed between sovereign countries to establish travel bubbles in order to protect public health and the relationships between countries.

Without these rules-based automatic exits, there is a risk of diplomatic fallout if countries experiencing spikes in Covid-19 cases find their travel privileges suspended. Indeed, the threat of temporary exclusions is also useful to motivate all countries to maintain high Covid-19 prevention standards and hence maintain their travel privileges.

Fourth, reopening should be managed with care. This is discernible in the Singapore-Malaysia arrangement's restricted list of who gets to be allowed in first. In the region-wide context, a similar gradual opening can, for instance, put healthcare workers, diplomats and business people in the priority list, followed by others such as students, and those travelling for family reasons and conferences.

Tourists should come in at the end, divided into short-term and longer-term visitors.

Finally, regulatory frameworks between governments are necessary but insufficient. Much more is needed and insurers, employers and healthcare providers will need to step up too.

Travellers don't just need to cross borders, they also need peace of mind. And this peace of mind will come from clarity on matters such as access to healthcare in each other's countries, coverage of travel insurance, repatriation processes and so on.

MUCH AT STAKE

Since March this year, almost all South-east Asian countries have instituted border controls to prevent the importation of Covid-19 cases.

These border controls have been helpful to buy time to ready countries for the surge in Covid-19 cases but they cannot remain in place indefinitely, especially since it may take several years to find, manufacture and administer an effective Covid-19 vaccine.

Reopening borders is inevitable despite the public health concerns.

Our trade, supply chains, food security, education and familial ties are simply too inter-linked to sustain prolonged border closures.

The critical question before us is, how do we safely reopen borders in South-east Asia in a way that protects public health, minimises disruptions and maximises effectiveness?

All of us are in uncharted territory and the Singapore-Malaysia pilot will be an essential precursor to an Asean travel bubble.

It is important that we draw as many useful lessons from it as possible and make the pilot work.

• Associate Professor Jeremy Lim is director of global health at the National University of Singapore's Saw Swee Hock School of Public Health. Dr Khor Swee Kheng researches global health and is based at the University of Oxford.