The appointment extends Farm's relationship with Polycell's parent company, ICI, after the agency picked up its garden woodcare brand Cuprinol in 2005.
The agency has been briefed to develop TV work to promote the Polycell range for floors and ceilings. The campaign will roll out across other media later in the year.
The Polycell brand last advertised in August 2004 with a TV spot created by the brand strategy and design agency Starchamber.
Peter Hunt, the director of marketing at ICI Paints, said: "We are delighted with the work Farm has been doing for us. It has worked with us to create strong advertising on Cuprinol, which has been highly effective in the marketplace. It seems a natural extension to have it alongside us with what are equally ambitious plans for Polycell."
Rob Smith, Farm's managing partner, added: "Like Cuprinol, Polycell is a fantastic brand with a history of strong consumer advertising. The brand has ambitious plans - so it's a great time to get involved."
Starchamber will continue to work on projects for ICI. Media planning and buying for the Polycell brand is handled by Initiative.