Sharon Bown's powerful words were delivered at a unique national commemorative service at the Australian War Memorial in Canberra - with just a platoon of television cameras, held inside the memorial.

Restrictions to hold back the spread of COVID-19 meant no public attendance, and no march to follow.

Ms Bown's great-uncle Private Albert Arthur Reader landed at Gallipoli 105 years ago - his name in bronze on the honour roll she stood next to as she delivered the Call to Remembrance.

"Let us do more than just honour those who have defended Australia," she said.

"In this time of crisis, let us realise the innate capacity within each of us to do the same - to unite and to protect the more vulnerable among us.

"To realise that the qualities for which we honour the Anzacs live on in each of us - endurance, courage, ingenuity, good humour, mateship and devotion, to duty to each other, to Australia."

The 16-year veteran is no stranger to tragedy and danger - she barely survived a helicopter crash, commanded a combat surgical team during some of the most intense fighting in Afghanistan, lost her mother to breast cancer and almost lost her policeman father to a homicidal psychopath.

Prime Minister Scott Morrison paid tribute to another nurse, Carolyn Griffiths, who joined the Reserves after the 2002 Bali bombings and served in Afghanistan and Iraq.

"Today, Squadron Leader Griffiths continues to serve as a reservist and as an ICU nurse at the Princess Alexandra Hospital in Brisbane where she works with one of her two daughters. The other daughter is a nurse at the Royal."

He noted having spoken a few days ago with Afghanistan veteran and Corporal Matt Williams, a brain cancer survivor and campaigner.

"Willie is in isolation today because his immune system depends on all of us keeping our distance," Mr Morrison said.

"He has served us, but now we must do the right thing by him and so many more because we are all in this together. But we always have been and we always will be."

Amid the quietness of the war memorial, Mr Morrison reflected on a 1919 gathering in Gallipoli.

"A small group of Anzacs who'd been arranging and tending the graves of their mates gathered and there was no pomp at that little service, there were no dignitaries, no band, just the sound of lapping water on the lonely shore," he said.

"One said of that little service, 'It was the real thing'.

"And so our remembrances today, small, quiet and homely will be."

Mr Morrison, Governor-General David Hurley, New Zealand High Commissioner Dame Annette King and Opposition Leader Anthony Albanese were among the dignitaries to lay wreaths.

Mr Albanese said the COVID-19 restrictions had made it a "very difficult day".

"One of things today does as well, is to put in prospective the sacrifice that we are being asked to make today to keep Australians safe," he told Sky News.

"We're being asked to stay at home."

Australian high commissions and embassies around the world have taken to social media platforms to enable expats commemorate Anzac Day.

Global travel restrictions because of the pandemic have prevented traditional Anzac ceremonies abroad taking place, such as at Gallipolli, Kokoda,and Villers-Bretonneux.

"While this year is different, we can all still mark Anzac Day," Foreign Affairs Minister Marise Payne told AAP.

"Our embassies and high commissions are playing an important role to bring Australian expats together to commemorate virtually."

Australian Associated Press