Masses of Haitian voters flocked to polling stations on Tuesday to participate in the long-awaited presidential and parliamentary elections, overwhelming election officials who struggled to handle the large turnout.

"The people have voted massively," said UN special envoy Juan Gabriel Valdes after election officials extended the voting period for several hours.

Voters queued in long lines patiently in the capital outside polling stations which were opened three hours late, defying temperatures above 30 degrees Celsius.

Authorities said that polling stations would not close until all the people had gotten their chance to vote.

"I don't mind waiting for two, three even four hours, to vote: I have already waited two years," a young Haitian told Xinhua.

In a polling station in the capital's Sonapi Industrial Area, a chaotic atmosphere reigned, and election staff offered help to voters.

Roadblocks were set up on the street outside the polling station and motorbikes were banned, outlawing the most popular transport tool used by foreign journalists.

Authorities said that during the last Haitian elections, a large number of murders and assaults were committed by motorcyclists.

Former members of Haiti's now-defunct armed forces, frequently a source of violence in the past, have called on Haitians to vote peacefully.

But there still have been three people killed in election-related violence, according to local media.

Two deaths occurred in Gros-Morne in the north of Haiti, while another one was killed and several injured in the capital in stampedes caused by voters trying to get their votes registered in polling stations.

Opinion polls give former president Rene Garcia Preval a substantial lead.

Garcia returned to the northern Haitian town of Marmelade, where he grew up, on Monday night.

The elections, which had been postponed four times for security reasons, were being observed by the UN, the European Union, the United States' National Institute for Democracy and the International Organization of Francophones.

Haitians were to elect the president, 30 senators and 99 deputies in the elections. To win outright, a presidential candidate has to win more than 50 percent of the votes.

Source: Xinhua