Papua New Guinea Prime Minister Peter O'Neill has resigned, Trend reports with reference to ABC.
After seven years in the top job Mr O'Neill told a media conference in Port Moresby that recent movements in Parliament had shown a "need for change".
He has handed over leadership to Sir Julius Chan, who will become prime minister for the third time.
The announcement follows weeks of high-profile defections from his Government to the Opposition.
On Friday, one of Mr O'Neill's key coalition allies abandoned him.
The Opposition bloc has since been saying it has 62 MPs in its camp, which would give it a majority in Parliament.
The resignation will be formalised when Mr O'Neill visits the Governor-General.
Earlier this month, he staved off an attack on his leadership by adjourning the country's Parliament for three weeks ahead of a planned vote of no confidence in him.
Despite insisting it would have a majority, the Opposition bloc that was trying to oust Mr O'Neill fell short of the numbers.
Having resisted calls to resign for weeks, Mr O'Neill has now accepted that he no longer has the support to maintain his leadership.
Sir Julius previously served as prime minister between 1980 and 1982 and from 1994 to 1997.