The Federal Government will help evacuate the hundreds of Australians stranded on the Diamond Princess cruise ship off Japan.

Key points: A charter flight will fly Diamond Princess passengers from Japan to Australia on Wednesday

A charter flight will fly Diamond Princess passengers from Japan to Australia on Wednesday The cruise ship has reported 355 cases of coronavirus, including 70 people diagnosed in the last day

The cruise ship has reported 355 cases of coronavirus, including 70 people diagnosed in the last day Returning Australians will have to spend two weeks in quarantine in Darwin before returning home

More than 200 Australians are on board the ship and 26 have tested positive for the coronavirus COVID-19.

An additional 99 passengers tested positive for the virus on Monday, raising the total to 454.

Prime Minister Scott Morrison said a Qantas charter flight would fly the passengers from Japan to Australia on Wednesday.

Upon arrival in Darwin, they will enter a 14-day quarantine period before they can return home.

"I understand that those who were on board will feel very frustrated about this, as well as their family members," Mr Morrison said.

"I am very frustrated about it. But, our first responsibility is that we have to protect the health and safety of Australians in Australia today."

Australians on board the ship told the ABC they were resigned to another 14 days in quarantine.

"[We're] not really being given any other option," one passenger said.

Earlier on Monday, Health Minister Greg Hunt said the number of confirmed cases on the Diamond Princess had reached 355, including 24 Australians, with 70 new cases confirmed in the previous 24 hours.

Japanese officials confirmed on Monday afternoon that 99 more people were infected, bringing the total to 454. Two Australians are believed to be among the new cases.

Chief medical officer Brendan Murphy said the second stint in quarantine was crucial because there were growing numbers of infections on the ship.

"The Australians who have been quarantined over the last 12 days, many of them have done everything that they have been asked to do and they are probably wondering why we are imposing this extra requirement," he said.

"We are not quite sure why there have been ongoing infections, but given there has been recent cases, we cannot be absolutely sure that any of the currently well people on the ship who are coming home on Wednesday are not carrying the virus.

"We cannot be sure and if we cannot be sure, we have to take precautions."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 40 seconds 1 m 40 s Australian on board Diamond Princess says she feels 'kept in the dark'

Tension has been building on the ship, with Australians complaining they had been left in the dark about their future as more than 400 Americans were evacuated from the luxury cruise liner.

Passengers have told the ABC they were getting the bulk of their information from the media.

Mr Morrison said Diamond Princess passengers who do not return on the charter flight would have to remain outside Australia for two weeks before returning home.

"We recommend they take up the option of being on that flight being provided for by the Australian Government," he said.

"It will make sure their health and wellbeing is taken care of on the return to Australia. Then they can return home to friends and family, as soon as possible after that."

The Americans, Canadians and Hong Kong residents that have been evacuated also have to spend anther 14 days in quarantine before they can return home.