The $40 million makeover of Wellington's Government House is complete and members of the public are being invited to take a look inside for the first time in four years.

The conservation of the large, two-storey wooden house, which dates back to 1908, began in October 2008. Open days in April will give the public an insight into the house which is a venue for credentials ceremonies for overseas ambassadors, state dinners and welcomes and the swearing in of cabinet ministers.

There are also functions to support community groups and charitable organisations.

Governor General Sir Anand Satyanand will officially re-open the house on March 24.

The open days will be held on April 9 and 10 between 10am and 3.30pm.