A show of hands was needed after the voting system broke

The amendments, which mean parliament could elect the next president, were carried by a vote of 276 in favour.

The vote was made by a show of hands after opposition members reportedly broke the electronic voting system in scuffles in the chamber on Tuesday.

Some MPs even sang songs and blocked the rostrum in a bid to stop the vote.

The proposals were drafted by supporters of President Leonid Kuchma.

Second vote

Under the new bill the presidential elections would still go ahead as planned next year but the winner would only sit for a two-year term instead of four. From 2006 the next president would be elected by parliament instead of the public.

Mr Kuchma is only allowed to serve two terms, but opposition parties fear the changes could mean he will attempt to prolong his rule or at least ensure a loyalist takes the post.

Our determination is based on the constitution of Ukraine and the feelings of society Boris Tarasyuk Our Ukraine

Boris Tarasyuk, one of the leaders of Our Ukraine opposition coalition, said he was disappointed the vote was approved on Wednesday, but insisted protests would continue.

"Our determination is based on the constitution of Ukraine and the feelings of society," he said.

Some opposition groups have said there were not enough hands in favour of the vote, and that the results were falsified in favour of the government.

They also allege that the whole measure is unconstitutional, and will appeal to the Council of Europe.

Ukrainian Communist leader Petro Symonenko defended the use of a show-of-hands vote.

He told Russian Channel One TV: "The constitution requires us to vote in person and in public. Because the system we use to vote is not functioning, we proposed that each of us who was in the chamber should raise his hand."

The amendments must pass in a second vote, which requires a two-thirds majority for approval. A date for the final vote has not yet been scheduled.