Parliamentary wing of the National Resistance Movement has officially launched boycott of products from companies it claims are supporting Jubilee.
The National Super Alliance (Nasa) MPs on Friday listed Safaricom, Bidco and Brookside as some of the firms whose products and services their supporters should boycott.
"We will resist the products of these companies because they are beneficiaries of the regime that killed people in this country," said Suna East MP Junet Mohammed.
The opposition alliance gave its supporters five days to find alternative products, saying the move is just the beginning of economic liberation in Kenya.
Nasa accuses Safaricom of aiding rigging of August poll in favour of President Kenyatta, a claim the firm has denied and dismissed.
The Raila Odinga-led coalition, on the other hand, accuses Brookside and Bidco of funding President Kenyatta's Jubilee Party.
"These companies have denied Kenyans their right to elect their leaders in a democratic process," Mr Mohamed said.
The MPs said they would start outreach programmes to tell their supporters about the boycott and alternatives.