Gold Coast police believe a Blues supporter who robbed a Labrador service station may have watched the game somewhere public.

Wearing a New South Wales Origin cap, the man used a large hunting knife to hold up the business on Frank Street around 2.40am, making off with a small sum of money.

Detective Acting Inspector Mark Procter said the offender's breath and movements indicated he had been drinking.

"He appeared intoxicated, so we're asking anyone who may have seen him at some sort of function earlier that night, maybe watching the football at some venue, if they recognise him," he said.