A tender for the giant cotton farm closed last night with Cubbie representatives saying five buyers were interested.

The station holds more than 530 billion litres of water when full - enough to supply Melbourne for more than a year - and there was speculation the Rudd Government would buy it in a bid to secure more water for the ailing Murray Darling river system.

But a Government spokeswoman said it would not be bidding. "This decision was based primarily on value for money concerns," she said, with uncertainty over Queensland water rules having contributed to the decision.