He has not replied to a request to his office to get the ball rolling on the process of selecting an artist, a Senate Estimates hearing was told on Monday.

Department of Parliamentary Services secretary Carol Mills said she wrote late last year to former prime ministers, Mr Rudd and Julia Gillard, along with former Speaker, Anna Burke, about commissioning their official portraits.

"I haven't yet heard back from Mr Rudd's office or from Mr Rudd,'' she said.

An official from Ms Gillard's office had replied about the process.

The National Portrait Gallery is arranging viewings of portraits to help former MPs decide on the style and artists for their portrait.

Department staff are working with Ms Burke to shortlist artists to paint the former Speaker's portrait.

Ms Mills said the official portrait of outgoing Governor-General Quentin Bryce should be finalised soon but could not provide a date for the unveiling.

Artists were paid $30,000 for an official portrait which was less than their usual fee but they were keen to have their works hung in Parliament House, the hearing was told.

The National Portrait Gallery has to approve the final portrait before it is accepted.

Asked if the person sitting for the portrait had to approve the work, Ms Mills said: "Technically no.''

"One would hope one would know before you saw the final product because it's quite an involving process between the sitter and the artist,'' she said.