Massmart's foray into grocery retailing is being contested by South Africa's retail heavyweights as it claims that exclusive leasing agreements are restricting the expansion of its Game stores.The lack of access to shopping centres had had an "acute" effect on rolling out Game stores, said Massmart's senior counsel Michael van der Nest this week.Van der Nest was representing the Walmart-owned general merchandiser at a Competition Tribunal hearing at which Shoprite, Spar and Pick n Pay were objecting to Massmart's application for a hearing."The problem is the exercise of that right to refuse us access. The network of exclusive leases impedes us from entering and expanding to compete in the national market, where these three players are large and dominant retailers for grocery in South Africa," said Van der Nest.Exclusivity clauses undermined Massmart's ability to roll out a competitive offering on a national scale "for the benefit of consumers", he said. Exclusive lease clauses "stifle market competition, to the detriment of consumers But whether Game stores will be able to compete with the big food retailers is unclear.Kaeleen Brown, a retail analyst at Standard Bank Securities, said there had been speculation about the success of the Game format. "It's difficult to say how well the addition of food is working, given the disclosure."Brown had rated Massmart shares as a "sell" since 2014 because the stock was expensive relative to its peers."They have underperformed the JSE and the shares have underperformed their peers. But they have performed well this year from a very from the beginning of the year," Brown said.Since the second quarter of 2014, Massmart's stock has risen by about 4%, while Pick n Pay's, Shoprite's and Spar's have grown by about 49%, 23% and 68% respectively.The All Share index rose 18% in the same period.Game is part of the group's Massdiscounters division, with 118 stores in South Africa, 110 of them in shopping centres.Asked about Game's performance, Massmart corporate affairs executive Brian Leroni said: "We prefer not to comment about the specifics of our food and grocery proposition while this matter is before the Competition Tribunal." Kyle Rollinson, an equity analyst at Avior Capital Markets, rates the stock as underperforming and said Game had fallen short over the past couple of years, lagging behind other divisions in the group such as Massbuild and Masswarehouse."Game has battled to get things right and it's obviously been a bit of a challenge with the food stores there. What's going to drive food products at Game when there's a Checkers in the same mall, or there's Checkers or Pick n Pay nearby?" he said.Leroni said exclusive lease clauses "stifle market competition, to the detriment of consumers", creating a sense of "contractual entitlement that represents a cynical attempt to maintain the status quo by closing the door on new competition".David Unterhalter SC, for Pick n Pay, said Game's expansion in shopping centres relied on "presumptive dominance".Shoprite counsel Jeremy Gauntlett SC argued that there was an overlap between the Massmart complaint and the inquiry into competitive practices in the retail grocery market, expected to complete its investigation by the end of May next year.In Massmart's latest sales update, total sales for the 26 weeks to June 26 increased to R42.3-billion, while Massdiscounters sales increased by 7.6% compared to 2.4% in the same period last year.The stock gained 0.64% to close at R145.01 on Thursday...