Westpac Stadium is skating on thin ice with its liquor licence.

It's been revealed an under-ager was served alcohol at the Black Caps Cricket World Cup quarter final against the West Indies in March.

Stadium CEO Shane Harmon said it's the second strike on the record of caterers Spotless, and another one could be hugely costly.

"Three strikes on a license means the license could be reviewed and potentially cancelled."

Harmon said it's very disappointing.

He said that while there were 30,000 people in the stadium, there are no excuses and they have to do better.

Harmon said the stadium does everything it can to prevent things like this happening.