Former Labour finance minister Michael Cullen has announced he will resign from Parliament at the end of April.
From 1 May, Dr Cullen will become a director on the board of New Zealand Post and will take over as deputy chairman in October.
He will also become principal adviser to the chairman of Waikato Tainui, Tuku Morgan, the former New Zealand First MP.
Dr Cullen is also awaiting an invitation from Ngati Tuwharetoa to assist that iwi with its Treaty claims.
Dr Cullen, the former deputy Prime Minister, entered Parliament in 1981 as MP for St Kilda in Dunedin. He became a list MP after the 1999 election.
He says he did not intend to see out this parliamentary term, though defeat at the 2008 election has hastened his departure and he does not regret leaving.
"When you've had 27-and-a-half years (including) 17 years as Labour's finance spokesperson, 12-and-a-half years as deputy leader, nine years as Minister of Finance, six years as Deputy Prime Minister you can scarcely have any complaints about leaving."
Dr Cullen says he has no problem working under a National government led by John Key.
Labour Party leader Phil Goff says Parliament will miss Dr Cullen, whom he describes as "father of the House", as he knows the rules better than anyone else.
Mr Goff welcomed Dr Cullen's appointment to the board of New Zealand Post as he had valuable skills and experience.