The consumer watchdog has warned businesses not to price gouge after the carbon tax is introduced next year.

Australian Competition and Consumer Commission (ACCC) chairman Rod Sims says organisations must not use the tax as an excuse to increase prices more than necessary or mislead consumers.

In an address to the West Australian Chamber of Commerce and Industry, Mr Sims said the ACCC wanted to ensure consumers were not “duped” into accepting prices they would not otherwise abide.

“If a business raises its prices and says the increase is a result of carbon pricing, or even partly the result of carbon pricing, it must ensure that what it says about the price increase is true,” Mr Sims said.

“Businesses can raise or lower their prices at any time. They are free to raise their prices today, and on July 1, 2012.

“But it is misleading conduct to say a price increase is due to carbon pricing, or even partly due to it, when that isn’t the case.”

Companies that face increasing costs from suppliers after the introduction of carbon pricing must also confirm their real cause before passing them on to their customers, Mr Sims said.

He used the address to launch the ACCC’s Carbon Price Claims guide for business.

The carbon tax comes into effect on July 1 next year.