PORT OF SPAIN, Trinidad (AFP) — Trinidad and Tobago heads for a tight race in tomorrow's snap elections called by Prime Minister Patrick Manning, with crime and corruption key concerns in the energy-rich Caribbean nation.

Manning called the elections mid-way through his five-year term in the former British colony where politics have long been divided along lines of Indian or African descent.

His People's National Movement (PNM), which draws support from Afro-Trinidadians and has dominated politics for half-a-century, faces a tough battle against a five-party coalition.

The "People's Partnership" is seeking multi-ethnic support and is led by Kamla Persad-Bissessar of the main Opposition United National Congress (UNC), which relies on Indo-Trinidadian backing.

Persad-Bissessar is hoping to become the Caribbean nation's first female prime minister and has a former campaign strategist for US President Barack Obama helping promote her message for change.

Opinion polls suggest a close race in the vote for a simple majority of seats in the 41-member Parliament, where the PMN now holds 26 seats and the UNC has the remaining 15.

The Manning administration has been under fire for spending millions of dollars on giant building projects and for hosting both the Summit of the Americas and the Commonwealth Heads of Government meetings last year.

Critics say many ordinary people have seen few benefits from the mushrooming development backed by revenues from rich natural gas and energy resources.

Manning dissolved Parliament in April shortly before a vote of no-confidence amid corruption allegations, which have recently hurt both main parties.

The Opposition is campaigning against crime on the twin-island nation where the murder rate has shot up dramatically in recent years.

Many blame the rising insecurity on the country's growing role as a transit point for South American cocaine.

An alleged death threat against Persad-Bissessar and an attack on her official car intensifed concern in the run-up to the elections, as did an alleged plot to disrupt the vote.

"Insecurity is the key issue. Manning is vulnerable on this, but the Opposition cannot assure voters that it would be very different if the Government changed," said Victor Bulmer-Thomas, Associate Fellow of the Americas at the Chatham House think-tank in London.

Analysts say the Opposition also faces a challenge to form a unified force in the diverse nation of some 1.3 million.

The coalition also includes the multi-racial Congress of the People, or COP, and the National Joint Action Committee, Tobago Organisation of the People and Movement for Social Justice.

Music in the nation famed for calypso has played a key role in campaigning.

One PNM video shows red-clad crowds dancing at rallies in front of a smiling Manning, with slogans such as "free education" sliding across the screen to a catchy tune.

On the other side, a People's Partnership campaign song contains the lyrics: "Allegations here, allegations there," and shows pictures of flashy high-rise buildings alongside hospitals without beds.

"I can't vote for that!" rings out the chorus.