More than 50 Greenpeace activists staged protests at two Unilever sites – a factory in Port Sunlight, on Merseyside, and at the Anglo-Dutch conglomerate's headquarters, Unilever House, on Victoria Embankment in London.
The lobby group is also targeting the offices of Unilever's marketing services agencies including the ad agency Ogilvy Advertising, and public relations specialists Jackie Cooper and Lexus PR.
The group has urged staff at the agencies to put pressure on Unilever into changing the behaviour of its palm oil suppliers.
The action coincides with a new Greenpeace report published today entitled 'How Unilever Palm Oil Suppliers are Burning Up Borneo'.
The report says companies that supply Unilever with palm oil for use in products such as its Dove skincare range are destroying the Indonesian rainforest.
Greenpeace claims Unilever is probably the largest corporate consumer of the oil in the world.
James Turner, a spokesman for Greenpeace at the Victoria Embankment protest, said eight people dressed as orang-utans had climbed ladders to reach a seven metre high balcony above the entrance of Unilever House.
He said: "It is going fairly well. We have got a lot of staff to talk to and a lot did not know about the destruction of the rainforest.
"Companies supplying palm oil are destroying the habitats of orangutans and massively accelerating climate change."
Unilever said it was addressing many of the concerns Greenpeace had aired about the expansion of palm oil production.
The company heads the Roundtable on Sustainable Palm Oil coalition of organisations, which has Oxfam, WWF, plantation owners, manufacturers and retailers on its committee.
It also has produced criteria for sustainable palm oil production.