Amir Hamzah Ibrahim, deputy police chief of northeastern Kelantan state, said 171 people - including foreigners from 36 countries - who took part in the Rainforest Challenge competition have been marooned in their vehicles since Friday.
Police rescued 28 of them by boat Monday and expected to bring in 40 more people later in the day, he said.
The remaining 103 people are still trying to make their way in 40 vehicles to a designated pickup point but progress has been slow because of floods and bad weather, he said.
"We've made good progress so far to evacuate them," Amir said, adding that he hopes to complete the rescue mission by Tuesday.
Police initially wanted to use a helicopter for the rescues but bad weather hampered airlift operations, he said. Continuous rains have raised water levels and allowed boats to enter the rocky terrain, he said.
Ten of the women trapped in the jungle were reported to be weak and two men, a Lebanese and a Chinese national, who were rescued complained of back pains, but there were no serious injuries, Amir said.
Police commandoes have been sent in on foot to deliver food to those trapped, he said. Some 100 police personnel and 10 boats have been mobilized in the rescue operation, he added.
The organizer of the expedition could not be reached for comment. The New Straits Times newspaper said the annual event attracted 350 competitors in 120 vehicles from 46 countries. It began Dec. 1 and was scheduled to end Monday.
Malaysia's east coast suffers flooding during the annual monsoon season. This year, seven people died and more than 4,000 people were evacuated in several states as heavy rain led to flash floods.