At the National Commodity and Derivatives Exchange, refined soya oil for delivery in September month advanced by Rs 1.40, or 0.22 per cent to Rs 632.50 per 10 kg with an open interest of 97,340 lots.
Similarly, the oil for delivery in August contracts moved up by Rs 1.15, or 0.18 per cent to Rs 628.80 per 10 kg in 60,820 lots.
Traders said widening of positions by participants on the back of rising demand in the spot market against tight stocks position on restricted supplies from producing regions mainly kept refined soya oil prices higher at futures trade.