Winston Peters is promising to boost the wool industry by forbidding the use of synthetic carpets and insulation in government-funded buildings if NZ First is part of the next government.

"Whether a government office or a Housing New Zealand property, where carpet is specified it will be natural wool or fibre from here on in," he said on Monday.

"New Zealand First will swing government procurement in behind natural, renewable and sustainable wool and natural fibres."

Mr Peters is in the South Island on his regional campaign tour, and he's pitching his new policy at wool growers.

He said 20 years ago wool was a $1 billion a year export and it's fallen to $531 million.

"Wool and natural fibres are wonder products and government can help take them to the next level," he said.

The Taxpayers' Union described the policy as "a refreshing step back to the 1970s".

"Carpets, as well as all other government supplies, should be selected on value for money alone," said executive director Jordan Williams.

"This sort of crony favouritism by politicians is exactly the sort of thing which sent New Zealand bust in the early days of Peters' career."