While one Melbourne eatery celebrates the discovery of a lost Mirka Mora mural, another is under fire for covering one of her heritage listed works in an apparent permit breach.

The owners of chain "pasta bar" Sauced have obscured a mural on the southern wall of the former Mirka at Tolarno restaurant in St Kilda, which was run by Ms Mora and husband Georges in the 1960s and 1970s.

Wooden beams and chip board have been erected a few inches in front of the mural, obscuring at least a third of the artwork.

Heritage Victoria gave Sauced co-owners Ben Thompson and Sylvan Spatarel a permit to renovate windows at the Fitzroy Street address.