The society, which is aiming to break through the 700-store barrier within three years, is publicising its internet initiative with a press advertising campaign.
The move follows in the footsteps of Lidl, Aldi and Farmfoods, all of which have sections on their websites designed to appeal to potential site vendors.
On the website, United Co-operatives, which trades in the north of England and north Wales, says a fee will be offered for the introduction of a site that leads to a successful deal. Users will be invited to subscribe to the site, www.unitedacquisitions.co.uk, and in return receive an email newsletter.
The society, which has just added 60 stores to its portfolio after completing the acquisitions of the Leeds and Sheffield Co-operative Societies, taking store numbers to 589, has put aside £150m to fund its growth plans. Over the next three years, £60m-£70m is earmarked for fresh acquisitions and 150 new store openings, with £80m-£90m for modernising existing stores.
"We are always seeking opportunities to acquire stores and this website is a valuable new tool that will allow us to build relationships with potential vendors and deepen our knowledge and insight of the current commercial property market," said Derek Fogg, United Co-operatives general manager, property group.
"The website has only just been launched so it is early days for us as far as possible site offers are concerned."