The benchmark palm oil contract for July delivery on the Bursa Malaysia Derivatives Exchange was down 0.9 percent at 2,100 ringgit ($508.47) a tonne, heading for a third consecutive session of falls.
Earlier in the session, it hit its lowest level since April 1 at 2,099 ringgit, and has declined 0.3 percent so far this month.
Palm oil may break a support at 2,110 ringgit per tonne and fall towards the support at 2,083 ringgit, said Wang Tao, a Reuters market analyst for commodities and energy technicals.
"Dalian and soyoil prices are still weak," said a Kuala Lumpur-based futures trader, referring to related edible oils on China's Dalian Commodity Exchange and soyoil on the U.S. Chicago Board of Trade.
Weakness on the energy front also weighed on palm prices, said another trader.
Oil prices fell on Monday, extending a slump from Friday that ended weeks of rallying, after U.S. President Donald Trump demanded that producer club OPEC raise output to soften the impact of U.S. sanctions against Iran.
In other related oils, the Chicago May soybean oil contract declined 0.4 percent on Friday, but was up 0.1 percent on Monday.
Soybeans have been under pressure amid concerns about demand from top buyer China, which is locked in a trade row with the United States, and the spread of African swine fever in China's hog herd. Soy is a key feedstuff for hogs.
Meanwhile, the May soyoil contract on the Dalian Commodity Exchange fell 0.6 percent, and the Dalian May palm oil contract declined 0.4 percent.