The bonds of mateship and sacrifice Australia and Papua New Guinea forged in the Second World War are enduring, Prime Minister Malcolm Turnbull has declared.
This year marks the 75th anniversary of the Kokoda Trail campaign and Mr Turnbull laid a floral wreath at the Isurava memorial on Saturday, during his official visit to PNG.
"This morning at Isurava we stood on what was in 1942 the hinge of fate," Mr Turnbull told reporters.
"Australia's freedom depended on courage, endurance, mateship and sacrifice of those few Australians and Papua New Guineans who stood together and held back the Japanese advance."
An estimated 625 Australians were killed along the track and more than 1600 were wounded. Casualties from sickness exceeded 4000.
Local Papua New Guinean men, dubbed affectionately the 'Fuzzy Wuzzy Angels', assisted and escorted wounded and injured Australian soldiers along the trail.
Mr Turnbull noted the Japanese tried to take Port Moresby three times but they were rebuffed in the Battle of the Coral Sea, held back on the Kokoda Track and defeated at the Battle of Milne Bay.
He later honoured the thousands of war dead at the Bomana, the largest war cemetery in the Pacific with close to 4000 graves, mostly Australian, just outside the capital Port Moresby.
"This is a solemn place, a momentous place. It is a place where we should remember that sacrifice," he said.
"Had the battle gone the other way, had their courage not been enough, had their mateship not been resolute enough, the Japanese would have taken Port Moresby," he said.
"Australia would have been under the most direct and imminent threat."
Mr Turnbull later held bilateral talks with Prime Minister Peter O'Neill, who will shortly face voters in the country's elections in June.
Australia will send a team to monitor the election and has been skilling up PNG's electoral commission.
The leaders discussed the logistical challenges around Port Moresby hosting the APEC leaders summit in 2018.
Australia is expected to contribute a large portion of the cost and recently announced $48 million in funding to extend the presence of 73 federal police officers in PNG until after the November summit.
Officers are helping PNG police plan security arrangements.
The prime ministers also talked about the closure of the Manus Island immigration detention centre by year's end and the fate of refugees who aren't accepted for a US resettlement deal.
The PNG Supreme Court last year found the detention centre breaches the country's constitution.
"Work is progressing quite well on processing the refugees," Mr O'Neill told reporters.
Mr Turnbull said Australia would do more to help PNG protect its maritime territory from illegal fishing and leaders also discussed trade and investment.
In March, PNG made a surprise request for direct budget support from Australia to pay for schools and hospitals. But the request has been rejected.
The PNG economy has faced severe challenges as a result of the downturn in global commodity prices. The government's coffers are strained and it has been forced to raise taxes and cut spending.
Mr Turnbull leaves for India on Sunday.
