File picture of Malcolm Turnbull. [Photo/Agencies]

WELLINGTON -- New Zealand Prime Minister John Key on Tuesday congratulated Malcolm Turnbull on becoming Australia's new prime minister, saying the two countries' close relationship would continue.

"Australia remains New Zealand's closest bilateral partner. We enjoy close ties in all areas of our relationship, including in the trade, economic, defense and sporting areas, and I am looking forward to working with Turnbull to advance that," Key said in a statement.

"I would also like to acknowledge the positive relationship I have had with Tony Abbott. He has been a good friend to New Zealand. He has visited twice this year and our discussions have always been productive," he said.

"I am confident that the close relationship between New Zealand and Australia will continue under Turnbull's leadership."

Turnbull, who was elected leader of Australia's ruling Liberal Party on Monday, has cited Key as a leader to emulate.

"New Zealand Prime Minister John Key is the model for explaining complex issues and making the case for change, achieving significant economic reforms," Turnbull reportedly said.