A Magic Talk caller described Maori as "genetically predisposed to crime, alcohol and underperformance educationally" and "a stone-age people" in an offensive rant.

Magic Talk presenter John Banks, a former Auckland mayor and MP, failed to stop Tuesday's caller, instead thanking the man for his call, saying "if their stone-age culture doesn't change, these people will come through your bathroom window".

The exchange was posted on social media site TikTok, before spreading to other platforms.

By Wednesday, outraged social media users were petitioning Magic Talk advertisers to pull their support of the station.

Telecommunications giant Vodafone and TradeMe, a major online sales website, responded by saying they would.

The backlash extended to New Zealand Cricket (NZC) - given Magic Talk holds the rights to broadcast Black Caps matches - which said it was "disgusted and appalled by an indefensibly racist" exchange.

NZC suggested it could walk away from that broadcast deal, saying "should strong action not be taken NZC reserves its right to review its relationship with Magic Talk".

A third major sponsor, Kiwibank, said it was "removing our ads from the Magic Talk website and we'll be talking directly with (station owner) MediaWorks on how they could better encourage a diverse and inclusive NZ".

After a 30-year political career including two stints as a cabinet minister, Mr Banks is well known in New Zealand for his right-wing views.

The 74-year-old said he "was not racist" in an on-air apology, saying his views "could have been misconstrued as racist".

Magic Talk announced later on Wednesday they had dumped him as a presenter, a position he held for the summer break.

Australian Associated Press