The New Zealand Commerce Commission has postponed its rulings on the takeover bids for discount chain The Warehouse Group.

The commission will delay handing down its decisions on bids from Australian retail group Woolworths and the New Zealand Foodstuffs co-operative until 25 May.

Woolworths, Australia's largest retail group, acquired a 10% stake in Warehouse last year, while Foodstuffs also owns a 10% stake. Both are looking to acquire 100% of the discounter.

The commission is examining whether an acquisition by either party would substantially lessen competition.

The regulator received an application from the three Foodstuffs co-operatives seeking clearance to acquire Warehouse last December. Woolworths lodged a similar application in January.