Former prime minister John Key has joined Air New Zealand's board of directors in his first post-parliamentary job.

Air NZ chairman Tony Carter said Mr Key would be a director with the airline from September 1.

"When John Key announced he was stepping down as prime minister and moving to a new phase of life outside of politics, it became a priority for the board to try to secure his services as a director," he said.

"[Mr Key] will bring extensive international commercial experience, outstanding leadership skills, global perspective and a keen understanding of the tourism sector."

In a statement, Mr Key said he had been approached to join the board.

"I look forward to working with the board, chief executive officer and his executive team to see [the company] fulfil its potential," he said.

Air New Zealand's longest-serving director, Paul Bingham, is stepping down.

Mr Key resigned as prime minister suddenly last year and left parliament officially in March, but had been quiet about his plans for life after parliament.