The opposition wants to know if the Director General of Health was pushed or if he jumped.

It follows Stephen McKernan's announcement he is stepping down when his contract finishes in July.

Labour's state services spokesman Grant Robertson believes Mr McKernan's fate may have been sealed months ago when Health Minister Tony Ryall appointed Murray Horn to chair the National Health Board.

Mr Robertson says it is a classic case of jobs for the boys, as Mr Horn was Mr Ryall's purchase advisor who he then appointed to lead a Ministerial review of the health system.