Winston Peters has been forced to apologise for saying Simon Bridges employed an "ethnic and racist view" during a capital gains tax debate over Māori land in Parliament today.

The National Party leader brought up suggestions that some Māori land may be exempt from any such tax implemented by the Government.

"Will Māori land recovered under the Treaty of Waitangi settlements be exempted under the Government's proposed capital gains tax as Meka Whaitiri has suggested recently to The Gisborne Herald?" Mr Bridges asked.

Mr Peters, who was answering as the Acting Prime Minister due to Jacinda Ardern's absence, gave an answer that didn't sit well with Speaker of the House Trevor Mallard.

"Can I just say that this attempt to provide an ethnic and racist view on a very serious study is bound to fail," he said.

The Speaker then made Mr Peters withdraw and apologise as "he cannot suggest that member is racist".

After apologising Mr Peters answered the same question in a similar fashion but worded more carefully.

"Any suggestion that he is trying to put out there to try and put a wedge between the people of this country is bound to fail."