"Our president, Afonso Dhlakama, will be absent at the opening of the electoral campaign" on Sunday, party spokesman Antonio Muchanga said at a press conference.
He said Dhlakama's absence was the result of parliament's failure to ratify a peace deal signed last Sunday, which ended Renamo's 18-month, low-level insurgency and opened the way for party candidates to run in the October 15 elections.
Renamo's electoral campaign will be launched by the party's secretary general, Manuel Bissopo.
Many have interpreted Dhlakama's refusal to leave his hideout in the central Gorongosa mountains as a sign of distrust in the government, sparking concern that hostilities could resume.
Renamo waged a 16-year civil war against the Frelimo party, which has governed Mozambique since independence from Portugal in 1975.
A 1992 peace deal turned Renamo into the biggest opposition party, but it launched a campaign of highway ambushes and other attacks in 2002, accusing the government of excluding it from political and economic power structures.
The elections will pit Dhlakama against Felipe Nyasa, the Frelimo candidate to succeed current President Armando Guebuza. Daviz Simango, from the small Democratic Movement of Mozambique (MDM), is also running.
Renamo currently holds 51 seats in the 250-member parliament.
Last Sunday's peace deal foresees the integration of Renamo fighters into the army and police force, though details are still to be agreed on.