Christchurch Central MP Nicky Wagner has been promoted to minister outside of cabinet following Maurice Williamson's resignation.
Wagner will take on the customs, statistics, associate conservation and associate Canterbury earthquake recovery portfolios. Conservation minister Nick Smith will pick up building and construction while veterans' affairs and immigration minister Michael Woodhouse takes on land information.
Williamson quit his ministerial positions after it was revealed he had contacted Auckland police in connection with domestic violence charges against businessman Donghau Liu. The Pakuranga National MP had earlier lobbied colleagues to grant Liu's citizenship.
Wagner will be sworn in by the governor general on Wednesday.
Over the weekend, Mr Williamson would not rule out a return to cabinet.
On Breakfast TV this morning, Mr Key said that was not a realistic option at this point.