Singaporean Dilpreet Singh, who runs a technology start-up in Melbourne, has been exercising regularly and checking in more often with his business team as he tries to keep spirits up while living under lockdown in the Australian city.

The 40-year-old, who has been in the capital of Victoria state since 2012, said there is a lot of disappointment and anger at the lockdown against the coronavirus pandemic being tightened and extended for six weeks until Sept 13.

It is the toughest so far in Australia, and comes after some people infected with Covid-19 were found not at home isolating.

"It is a pretty bad mood here on average. Most Australians have listened to the government, so the mood is one of huge disappointment at the situation. There is a lot of anger and resentment at the few people who have spoilt it for the rest of us," said Mr Singh.

"I am personally doing okay - I am keeping up my running routine at the local stadium, interacting with my team a lot more to make sure everyone is fine," he said.

Under the tightened restrictions in Melbourne, people have to observe an 8pm to 5am curfew and stay within 5km of their homes during the day. Only one person per household can shop at a time once a day, while leaving the house to exercise is permitted for only one hour a day within a 5km radius.

Mr Singh said that it has been difficult to get hold of essential items such as toilet paper, bread and fruits in recent days.

There is also worry about the economic impact and jobs. "There has been a lot of negative news in terms of how businesses are going to fail, and suicides have been on the rise... I have not had to lay off anyone so far, and I am hoping to keep it that way."

Mr Singh said having communication limited to teleconferencing via platforms such as Zoom has made it more difficult to convince investors to come on board. In June, his application for an exemption to return to Singapore to seek investors and raise funds for his business was rejected.

Another Singaporean, first-year PhD student at Monash University Regine Lau, has been away from home since February.

While the 26-year-old would have preferred to return home to wait out the pandemic with her family and friends, she decided to remain in Melbourne as there was some uncertainty over when international students would be allowed back into Australia.

"Feeling homesick is something I have learnt to cope with, and FaceTime definitely helps. My family and friends had plans to visit me, but these had to be postponed," said Ms Lau, who is reading clinical neuropsychology.

She said there was panic buying initially. "When I went grocery shopping on Sunday... some people were panic buying. They were buying condiments and long-shelf-life milk by the dozens."

But when she made a second trip yesterday, she did not encounter any difficulties, and there were still poultry and produce on the shelves.

Singapore permanent resident Paul Falzon, 46, has been in Melbourne since mid-June to help take care of his father, who suffered a heart attack.

"I am doing long runs around the area, personal high-intensity interval training classes in the backyard and yoga just to keep fit and sane. It is more exercise than I have ever done before," he said.

He has also been calling his wife and nine-year-old daughter, who are in Singapore, two to three times a day.

Mr Falzon said: "I just hope the situation doesn't get worse than it is. I want to get back to my family. I miss them a great deal."