The men appeared in the High Court in Auckland on Monday after changing their pleas to guilty.

Four men involved in a drug ring that "got out of control" have pleaded guilty to a raft of charges at the High Court in Auckland.

Benjamin McLellan, Tafa Misapti, Samuel Montgomery and Mobeen Bhikoo all pleaded guilty to 28 charges relating to either supplying or possessing cocaine on Monday morning.

McLellan is a business manager who also appeared in a Fonterra advertisement campaign last year.

Montgomery is a clothing distributor, while Tafa Misipati is a personal trainer and professional kickboxer, whose fights have been aired on Sky TV.

Mobeen Bhikoo, who pleaded guilty to the most charges, is a well-known Auckland hairdresser. Amongst the cocaine charges, Bhikoo also pleaded guilty to possession of methamphetamine along with Misipati.

Fashion designer Christopher Lay had previously pleaded guilty to supply and possession of cocaine.

In a statement, Bhikoo said he had pleaded to reduced and amended charges related to supplying "close friends" with low-grade cocaine.

"I had access to the drug through another person I knew, and would get it and then others would get it off me," he said.

"I was not some some big wholesale or street dealer. At the time, we were all using the drug in our social circle. It started being social use only, but I accept we let it get a bit out of control," he said.

The ring was busted last year by police in a sting known as Operation Civiche.

A three-week trial had been set down to start on Monday for all four defendants, but they changed their please late last week.

They will be sentenced in November in front of Justice Sally Fitzgerald.