"The situation is one of calm and a massive voter turnout," Ana Gomes, the European Union (EU) chief observer, said. Officials said voting might be extended to midnight (2100 GMT) because of the queues at polling stations.
Opposition parties advocating a bigger role for free markets in the Horn of Africa country of 72 million have set aside their ethnic differences for the first time, pledging to unite if it means winning a majority in the 547-seat national assembly. However, many analysts say a victory over Meles's dominant Ethiopian People's Revolutionary Democratic Front (EPRDF) is unlikely, given the opposition currently holds a mere 20 seats.
In the run-up to the polls the opposition accused the EPRDF of trying to rig the result. The government denies this.
In Addis Ababa the stream of voters swelled throughout the morning at polling stations dotted among its mist-shrouded hills as church services ended and worshippers turned up to vote. Voters in the capital's Gullele sub-district cheered as a bride and groom resplendent in wedding dress arrived to cast their ballots.
Bereft of experience at the polls and subject to what they call harassment by ruling party cadres, opposition candidates have yet to mobilise grassroots support in rural areas, which is critical to their success, diplomats and analysts say. Nor does the opposition have a clear leading personality to challenge former guerrilla chief Meles, whose tough speeches have compared the opposition to Rwanda's ethnic Hutu Interahamwe militias and raised the spectre of ethnic bloodshed.
More than 300 foreigners are observing the polls, the most ever allowed at an Ethiopian election. Jimmy Carter, a former US president, is heading one of the teams.
Gomes said that in eastern Harar town, voters had complained of intimidation, saying the chairperson of their polling station said they were to vote for the bee, the EPRDF's election symbol.
In another area, police officers were seen controlling the crowd with sticks and guns, while people with machetes were allowed into the polling station, she added.
Ethiopians line up to cast their vote outside a polling station in Addis Ababa, Ethiopia Sunday, May 15, 2005 during the third democratic elections in Ethiopia's 3,000-year history.