Northern Star chairman Bill Beament has promised his enlarged company will lock in forward prices for no more than 15 per cent of gold production in the three years ahead, after hedges cost the top 10 gold miners on the ASX a combined $300 million in lost revenue over the past three months.

Northern Star and St Barbara surrendered the most revenue to hedges during the three months to December 31 after they honoured contracts that compelled them to sell gold at prices well below the daily market average of $2567 per ounce during the period.