Australia Day nightmare: Man makes grim discovery after biting into restaurant burger.

A horrified Perth man has allegedly bitten into his Australia Day beef burger to find a mouse.

Bruce Blackburn claims he found the mouse after biting into a meal at Inglewood’s Civic Hotel.

“Having Australia Day lunch and this is what Bruce got in his burger. Health dept issue… he bit into a full mouse… f—ing yuk….”, his partner Peta Blackburn posted to Facebook, alongside photo showing a dead mouse beside a burger.

Ms Blackburn’s post has attracted hundreds of comments, with many in disbelief that such a thing could occur in a restaurant.

Mr Blackburn told 9NEWS he was given a refund for the incident, but not an apology. He plans to report the incident to the Western Australia Department of Health.

Mamamia reached out to The Civic Hotel for comment, but they declined to respond.