A new 'restaurant for pilgrims' is driving Venice prices down by offering cheap, quality lunches to visitors to St Mark's Basilica.

The eatery, which advertises three-course lunches for a tidy 13 euros ($17), has yet to open but has already caused a flutter around the famously pricey square.

Three days before it threw its doors open to the public on Monday, reporters had already spotted ''new, competitive'' menus on sandwich boards in the area.

The La Basilica restaurant is run by a local catering company, SGS, on behalf of the St Mark's Procurators, the board that manages the famed Byzantine cathedral.

Since the Procurators are a non-profit outfit, SGS has been able to come up with a large menu for the lowest of costs, catering firm chief chief Augusto Piscella said.

''I was amazed,'' he said at the restaurant's unveiling Thursday night.

''Since all we have to do is break even, we can afford a choice of eight first courses, seven second courses and six side-dishes''.

''The Procurators' aim is to give a medium-high class meal to all those who visit the Basilica, expressing the Venetian Church's desire to welcome people''.