New Zealand Post's chief executive is leaving.

Brian Roche is leaving in April after formally giving his resignation.

He said it's time for someone new to take up the role, which he's had for almost seven years.

Mr Roche said he's going to be retiring from all full-time executive roles, to take up other business interests.

Chairman Sir Michael Cullen said Mr Roche has led New Zealand Post through a period of great challenges.