A Sydney couple celebrating 1000 days together have called out a "horrible experience" at a North Ryde restaurant on social media, publishing a video of a cooked steak that appeared to be crawling with live maggots.

Stella Kim and her partner Sushil Lamichhane​ were dining with two friends at The Ranch Hotel bistro on Wednesday evening when one of the three steaks they ordered arrived infested with what appeared to be small white worms or fly larvae.

"We ordered steaks and one of our steaks was full of worms. Live worms coming out of the steak. We couldn't believe this was happening at one of the big restaurant [sic] in Australia," Ms Kim said in the Facebook post, which has been viewed more than 140,000 times.

"I wish no one has to go through this horrible experience. We have lost our appetite."