The favourite kitchen tool of the home epicurean, the Thermomix, has left a Queensland senator mystified in parliamentary hearings.

Senate estimates hearings have been inquiring into the spending of Governor-General Sir Peter Cosgrove.

His office has put out a tender for $80,000 - $100,000 worth of kitchen equipment for the Governor-General's two residences - Yarralumla in Canberra and Admiralty House in Sydney.

Among the several items requested for the kitchens, one in particular stumped Labor senator Joe Ludwig.

"You're seeking four stick blenders, two food processors, a — and you're going to have to help me with this — a Thermomix?" Senator Ludwig asked the Governor-General's official secretary, Mark Fraser.

"I don't know what a Thermomix is."

That admission prompted one of his colleagues to tease, "Where have you been?"

"Queensland," he replied.

Senator Ludwig asked Mr Fraser to explain what a Thermomix is. But he, too, was at a loss.

"I don't know what a Thermomix is," he said.

"So there's a couple of us who don't know what a Thermomix is," Senator Ludwig declared.

Labor Senator Joe Ludwig admits he'd never heard of the Thermomix, a multifunctional food processor and cooking machine. ( AFP: Patrik Stollarz )

The Thermomix is billed by its manufacturers as "the most advanced kitchen appliance on the market today" that "unites the functions of 12 appliances in one compact unit".

They are popular but not cheap, costing about $2,000 per appliance.

Finance and Public Administration Committee chair and Liberal senator Cory Bernardi made it clear he was not ignorant of the food processing marvel.

"They're very popular amongst the home master-chefs of today," he told the committee.

"Is that the elite trendies that use that, are they?" asked Senator Ludwig.

"In Queensland, you may refer to them as that, I just refer to them as those who have a particular interest in cooking," Senator Bernardi said.

The Governor-General's kitchens also have a KitchenAid mixer, an upright freezer, a deep fryer and a pasta machine on their wish list.

"We have thousands of guests each year across both properties [Yarralumla and Admiralty House]," Mr Fraser said.

He said the appliances were needed to replace or renew other equipment in order to "maintain the proper functioning of the kitchen".

Senator Ludwig raised the spending when asking about other costs the Governor-General's office was incurring, including $168,000 on redundancies and around $250,000 on employing two more staff members.

"You wonder where the priorities are," Senator Ludwig said.