COVID-19 restrictions mean that veterans have to register to attend, but although up to 8000 veterans are expected to march, only 1400 have registered so far.

"It's a little bit surprising," RSL Victoria chief executive Jamie Twidale told AAP.

But he said the RSL has changed the rules for the April 25 march so that veterans can register when they arrive on the day.

"We'd hate to turn people away," he said.

Veterans will be asked to march with one of five groups, and it's hoped they will be able to make contact with others they served with so that they can march together.

Mr Twidale said with the cancellation on Anzac marches in 2020, veterans missed out on catching up with people they served with.

"That was a big drain on their wellbeing, especially during a pandemic," he said.

He noted that veterans may not wish to go out into large crowds due to the pandemic, and may have decided to commemorate the day locally.

Official Anzac Day marches were cancelled last year, leaving many Australians to stand in their driveways and light a candle at dawn.

Acting Premier James Merlino says World War II and Korean War veterans are especially vulnerable, and the average age of Vietnam War veterans is about 70.

"We want this event to go ahead. We want as large a crowd as we can," Mr Merlino told reporters on Wednesday.

A cap on numbers for the state's dawn service at the Shrine of Remembrance will remain at 1400 people.

But recently relaxed coronavirus restrictions mean 75,000 people will be able to attend the annual AFL match between Collingwood and Essendon at the Melbourne Cricket Ground just a few hours after the march.

Australian Associated Press