At the National Commodity and Derivatives Exchange, refined soya oil for delivery in August month inched up by Re 1, or 0.16 per cent to Rs 636.40 per 10 kg with an open interest of 30,910 lots.
Likewise, the oil for delivery in far-month September contracts traded higher by a similar margin to Rs 639.75 per 10 kg in 79,480 lots.
Traders said besides uptick in demand in the spot market, restricted supplies from producing belts mainly led to rise in refined soya oil prices at futures trade.