The Movement for Democratic Change faction led by Arthur Mutambara said police in Mashonaland West have barred two rallies there this weekend on flimsy grounds.
Police in Karoi refused permission for an MDC rally saying the venue, a rugby pitch, lacked sanitation facilities, while in Chinhoyi, authorities said the stadium in which the opposition faction wanted to hold a rally was still under construction.
Faction officials said they sought police clearance and were surprised to be refused.
Police have banned rallies in Harare and Chitungwiza citing security risks, but MDC officials in both opposition factions see this as a violation of their right to hold political rallies ahead of local, general and presidential elections in early 2008.
Deputy Spokesman Abednico Bhebhe of the Mutambara faction, the member of parliament for Nkayi, Matabeleland North, told reporter Jonga Kandemiiri of VOA's Studio 7 for Zimbabwe that the formation is considering defying the bans.