In July, Mr O’Neill accused the then Opposition leader of spreading ''nonsense'' and ''completely untrue'' claims over foreign aid linked to the Manus asylum seeker deal.
But an election win is always a landmark moment in politics, a point when the past is another place, and so today Mr O'Neill sent a letter to Mr Abbott congratulating him on his success.
"Your comprehensive win was demonstrably a true indication of the trust, confidence and support the Australian constituents have in your leadership qualities and more importantly the political, social and economic policies of the Liberal Party," Mr O'Neill said.
"Let me assure you that my government is committed to working closely with you and your government during your tenure and most importantly, in pursuit of our bilateral relations.
"Allow me on this wonderful occasion, on behalf of the government and people of Papua New Guinea, to offer our sincere congratulations on your election as prime minister of Australia."
PNG government sources have told AAP they expect the Abbott government to tinker around the edges of existing PNG policy but keep core programs.