The Prime Minister's chief of staff, Wayne Eagleson, has resigned.
Newshub's Patrick Gower reported that Eagleson - who was John Key's chief of staff for nine years - told Beehive staff of his decision today.
He will stay in the position for the next few weeks, allowing him to be involved in coalition negotiations with Winston Peters.
Eagleson holds huge power in Government and became an integral part of John Key's reign.
Gower reported Eagleson considered quitting alongside key but stayed on after a request from his friend Bill English.
Former National leader Don Brash first hired Eagleson and the close relationship he later formed with Key was compared to that shared between Helen Clark and her chief of staff Heather Simpson.
Before taking on the role Eagleson was a former researcher and private secretary to Jim Bolger and worked for companies including DB Breweries and grid operator Transpower.
The Prime Minister's office confirmed the resignation.