Key Points:

Christchurch Casino says it is reviewing its dress code and was already doing so when it received a complaint from a woman who says she was "humiliated" after being asked to cover her ample breasts.

English tourist Helen Simpson, 33, complained publicy after she says she was "absolutely humiliated" when a woman casino staff member told her to cover up or leave early last Saturday morning.

"She said I was wearing too low a top, which people found offensive," Ms Simpson told The Press newspaper.

"I was highly embarrassed - humiliated, absolutely humiliated.

"I feel like I've been discriminated against for having big breasts."

Ms Simpson said she didn't choose to be "well endowed in the upper region" and described herself as a "size 14 woman with the top half demanding a size 20".

Casino chief executive Brett Anderson said today he received a letter of complaint from Ms Simpson about the same time as the newspaper.

"We've a policy of addressing any complaints. She did not give us the opportunity to do so."

Mr Anderson said he would not discuss the issue "through the media".

However, having taken over the chief executive's role at the casino just six weeks ago he said he had already marked its dress code as an issue requiring his attention.

"Probably one of the biggest comments I've had since being in Christchurch is about the (casino's) dress code and how it has slipped," he said.

"I'd like to see the standard raised again.

"My intention is to give it a bit more teeth ... to enhance and enforce our dress code, because that is the feedback I'm getting from our clientele."

Christchurch Casino once had what was regarded as the strictest casino dress code in New Zealand, banning blue jeans, for instance, but had relaxed the rules in recent years.

Mr Anderson said he had discussed dress standards with staff before Saturday's incident involving Ms Simpson.

"Staff have been made aware of it and it's something we're following up on."