Labor senator Tony Sheldon questioned whether it was appropriate for an impartial ombudsman to rail against the opposition's pre-election proposal to raise the minimum wage.

"Our job really clearly, under the Act, is to advocate for policies in the interests of small businesses," Ms Carnell told a Senate estimates hearing in Canberra on Wednesday.

She said her role was to act on behalf of small businesses to make sure there were friendly policy settings.

"I will do that aggressively and enthusiastically whoever makes the comments," the ombudsman said.

"If you have a look through all of the work you do there is similar comments made against Liberal Party policy as well."

Senator Sheldon also questioned her about an ABC interview in which she said the Liberals "were in with a show" at next year's territory election if they proved they could be a centrist government.

But Ms Carnell said she made the comments as a former chief minister, with the story marking 12 months to polling day.

"Not terribly surprising for an ex-head of government to have a long-form interview of those sorts."

Senator Sheldon said Ms Carnell had supported the Fair Work Commission's decision to cut weekend penalty rates in some industries.

Ms Carnell said she supported feedback from small businesses that changes to weekend rates would make it easier to trade seven days a week and the independent umpire's decision.

Australian Associated Press