Bomana is the largest war cemetery in the Pacific with close to 4,000 graves, mostly Australian.

"Those who gave their lives and lie here are always in our hearts," Sir Peter told the crowd.

"Their deeds, their sacrifices and the battles they fought have shaped us."

He reflected on the pivotal role Australian troops played in PNG halting the Japanese advance, after Singapore fell and northern Australia was bombed.

"They were courageous and enduring in some of the worst conditions warfare can demand," Sir Peter said.

"Many would fall here in the jungle, away from the wide brown land they loved, but were destined never to see again."

He paid tribute to the bravery of Corporal Jack French, awarded a Victorian Cross for single-handedly taking out three enemy machine gun posts during the Battle for Milne Bay.

"Although badly wounded he continued to advance until fatally shot," Sir Peter said.

Sir Peter also singled out Sister Marie Craig, the only woman buried at the cemetery, who nursed the wounded and died in a plane crash.

The grave of Sir Peter's uncle Bill, a flight sergeant with the RAAF Beaufighter unit, who died in a plane crash, is among the thousands at Bomana.

It was equally important to remember the bravery of those who made it home and the few surviving veterans, the governor-general said.

"They have assumed the mantle of national treasurers, a living link to a time when our nation fought for its very survival," he said.

Sir Peter also lauded the efforts of local Papua New Guineans, known affectionately as the Fuzzy Wuzzy Angels, who helped injured and wounded Australian soldiers along the Kokoda Track.

"Stretcher bearers, guides, a shoulder to rest on par excellence," he said.

Opposition Leader Bill Shorten and his wife Chloe also travelled to PNG for Anzac Day commemorations.

"As the sun rises on these white stones we remind ourselves each one stands for a son, a father, a brother - someone who loved, who was loved and who never came home again," Mr Shorten told the dawn service at Bomana.

"In our nation's darkest hour, when Australia faced its sternest test, they paid the highest price."

An estimated 625 Australians were killed on the track and more than 1,600 were wounded. Casualties from sickness exceeded 4,000.