Zimbabwe police have deployed throughout the capital, Harare, in anticipation of a protest by a united group of opposition parties that includes a former vice-president.

The protest planned for Friday will mark the first time that the fractured opposition has joined in a single action to confront President Robert Mugabe's government since 2007.

Organizers say the demonstration will bring together at least 18 political parties and civic organizations, and will include opposition leader Morgan Tsvangirai and Mugabe's former deputy, Joice Mujuru.

Truckloads of anti-riot police have been deployed as well as water cannons, frequently used to break up anti-government protests in the past two months.

A court is expected to rule Friday on an application by the opposition parties seeking an order barring the police from interfering with the protest.