CONAKRY (Reuters) - The president of Guinea's national election commission on Wednesday said he will step down amid a political stalemate over parliamentary polls and following months of pressure from opposition supporters.

The mineral-rich west African nation has struggled to complete a transition to civilian rule since 2010 because the final step in the process -- parliamentary elections -- has been repeatedly delayed by disputes between rival political camps.

Opponents of Guinea's President Alpha Conde, who have taken to the streets in a series of protests resulting in violent clashes with security forces, had called for Louceny Camara to be sacked.

Speaking on state television, Camara asked his trade union supporters not to back him in a shake-up of the body, known as the CENI, expected to take place in the coming days.

"In the superior interest of the nation, I have asked my union who chose me as their delegate not to reelect me in the next restructuring of the CENI," he said.

"I took this decision to allow the electoral process to move forward calmly," he said, adding that he would continue to perform his functions until a new commission is named.

Camara is considered by the opposition to be an ally of Conde. The opposition accuses the president of attempting to consolidate power by pre-rigging the legislative polls in his favor.

A prolonged impasse over how the polls should be organized has caused the election date, initially meant to come on the heels of Conde's election in late 2010, to backslide repeatedly, worsening simmering political and ethnic tensions.

Two Guinean opposition ministers resigned from Conde's government on Saturday after a protest last week saw the arrest of more than 100 opposition demonstrators.

Guinean opposition parties have also said they will no longer participate in the National Transitional Council, which serves as an interim parliament, and will also boycott the national electoral commission.

Meanwhile donors to the world's biggest bauxite exporter have said they will only resume full cooperation with the country after the legislative election. Guinea also has massive untapped iron ore, gold and diamond reserves.

(Reporting by Samb Saliou; Writing by Joe Bavier)