FACTBOX: Major parties in Zimbabwe elections

(Reuters) - Following is a factbox on the major parties contesting Zimbabwe's elections:

ZANU-PF

In power since independence from Britain in 1980.

Formed in 1964 during white minority rule, and one of two parties that led the struggle for independence.

Merged with Joshua Nkomo's PF-ZAPU in 1987 after a five-year political rebellion in ZAPU's Matabaleland and Midlands strongholds.

Robert Mugabe has led ZANU-PF for over 30 years.

ZANU-PF won 62 of the 120 contested seats in the last general parliamentary elections in 2000 which were marred by violence and rejected as fraudulent by the opposition.

Mugabe says ZANU-PF -- which had a two-thirds majority in the last parliament elected on March 31 2005 -- must win this year's polls overwhelmingly to shame its Western critics.

MOVEMENT FOR DEMOCRATIC CHANGE (MDC)

Formed in 1999 and propelled by a wave of popular anger against Mugabe's policies.

Won nearly half of the contested seats in 2000.

The labor-backed MDC draws its support mostly from urban centers and the Matabeleland provinces.

Lost electoral ground in parliamentary elections in 2005 after years of a government crackdown.

It split into two factions in October 2005 following a bitter quarrel over political strategy and internal democracy.

Main MDC faction led by Morgan Tsvangirai. He says his party is confident of victory, but fears government rigging.

The other MDC group is led by Arthur Mutambara.