Venezuelan President Nicolas Maduro on Thursday proposed opening talks with the opposition before a much contested vote expected this weekend to elect a body that would rewrite the constitution.

"I propose to the Venezuelan political opposition that it abandon the road to insurrection... and that in the coming hours, before the election and installation of the constituent assembly, we begin a roundtable dialogue," Maduro said.

The offer came as a showdown looked imminent, with the Caracas government barring protests from Friday, and the opposition nevertheless calling for a nationwide rally.