KENYANS are voting in large numbers in an election that pits President Uhuru Kenyatta against challenger Raila Odinga amid fears the east African economic hub’s poll battle could spark deadly ethnic violence.

Kenyatta, voting in his birthplace of Gatundu, north of Nairobi, said: “I feel good. I feel positive because we ran a positive campaign.”

The 55-year-old, accompanied by his wife Margaret, his mother and two of his three children, urged Kenyans to vote peacefully and go home to await the results.

Odinga, 72, voted in the poor area of Kibera, an opposition stronghold in the capital Nairobi, and was surrounded by well-wishers.

He urged supporters to gather today in a central park for what he predicted would be a celebration.

Voters formed long queues at many polling stations before dawn, waiting for the chance to cast ballots in a tightly contested race for the presidency as well as for more than 1800 elected positions, including governors, legislative representatives and county officials.

A key concern was whether Kenya would echo its 2013 election, a mostly peaceful affair despite opposition allegations of vote-tampering, or the 2007 election, which led to violence fuelled by ethnic divisions that killed more than 1000 people.

Kenyatta, the son of Kenya’s first president after independence from British colonial rule, campaigned on a record of major infrastructure projects, many backed by China, and claimed strong economic growth.

Odinga is also the son of a leader of the independence struggle and has cast himself as a champion of the poor and a critic of endemic corruption in many state institutions.

Many people are expected to vote along ethnic lines. Kenyatta is widely seen as the candidate of the Kikuyu people, the country’s largest ethnic group, and Odinga is associated with the Luo voting bloc, which has never produced a head of state.

Reaction to the result could partly depend on the performance of Kenya’s electoral commission, which will collect vote counts from more than 40,000 polling stations.

Fears of violence were increased by the murder of an electoral official in charge of technology days ahead of the election.

The election commission has said that about 25 per cent of polling stations will not have network coverage, meaning officials will have to move to find a better signal and transmit results by satellite telephones.

By law, election officials have up to a week to announce results, though many analysts believe the outcome of the presidential race will be declared far sooner, possibly within one or two days.

The winner of the presidential race must get more than 50 per cent of the votes as well as a quarter or more votes in at least 24 of Kenya’s 47 counties, according to election officials.

If the front-runner falls short of those benchmarks, the two top contenders will contest a run-off vote.

Kenyatta and Odinga also faced off in the 2013 election. Kenyatta won by a thin margin, with just over 50 per cent of the vote. Odinga alleged voting irregularities and took his case to Kenya’s highest court, which ruled in Kenyatta’s favour by validating the results.

Kenya has nearly 20 million registered voters out of a population of more than 40 million.