At the National Commodity and Derivatives Exchange, refined soya oil for delivery in November declined by 70 paise, or 0.11 per cent, to Rs 664 per 10 kg with an open interest of 37,310 lots.
Similarly, the oil for delivery in October shed 10 paise, or 0.02 per cent, to Rs 661.90 per 10 kg in 33,590 lots.
Analysts attributed the weakness in refined soya oil futures to offloading of positions by traders owing to slackened demand in the spot market against sufficient stocks position.