Competitors cast doubt over Murray Goulburn's bid for Warrnambool Two of Murray Goulburn's biggest competitors have questioned its claim that a merger with Warrnambool Cheese and Butter would be in the public interest, saying the co-operative's proposal is ""highly speculative"." WCB, Australia's oldest listed milk processor, is the target of an intense bidding war between Murray Goulburn and one of the world's biggest dairy companies, Canada's Saputo. The Australian farmer-owned co-operative, which has offered $9.50 a share, or $533 million, argues that its bid will create a "super co-operative" giving Australia the scale necessary to compete globally. But in separate submissions to the Australian Competition Tribunal, Murray Goulburn competitors Parmalat and Fonterra cast doubt on the claim. ""Our view is that any public benefits are unclear and uncertain and would not overcome the detriments arising from the decrease in [local] competition,"" Parmalat general manager Nigel Ulrich said. ""The claimed public benefits would appear to be highly speculative and difficult for the Tribunal to be "satisfied" that they will eventuate."" Throughout the bidding, Murray Goulburn has said it hoped to emulate New Zealand co-operative Fonterra, which merged with another New Zealand co-operative, allowing it to become the world's biggest milk processor and exporter. But Fonterra told the Tribunal its merger was different to Murray Goulburn's proposal in ""nature and scale"." ""The Fonterra merger was underpinned by a series of voluntary regulatory behavioural constraints,"" Fonterra said in its submission. ""These constraints have been pivotal in ensuring that competition for milk at the farm gate was preserved, which is in turn key to the continues promotion of growth within any dairy industry."" But while Parmalat and Fonterra questioned Murray Goulburn's proposal, it seemed to find an unlikely ally in Bega Cheese, which was a bidder for WCB until it closed its offer last month, having acquired 18.8 per cent of the company. In a six sentence statement to the Tribunal, Bega executive chairman Barry Irvin said he did not believe Murray Goulburn's bid, if successful, would lessen domestic competition for milk. ""Bega Cheese believes there remains significant competition... even with a merger of MG and WCB,"" Mr Irvin said. Murray Goulburn's bid hinges on approval from the Competition Tribunal, which is set to make a decision on February 28. This compares with Saputo's unconditional offer of $9 cash per share closing this Friday. The Canadian company has indicated it may not extend its offer. Saputo announced on Thursday its stake in WCB had increased to 20.1 per cent.