The Election Commission (EC) said the poll went smoothly in the 76 provinces nationwide yesterday.

It said that voting was largely peaceful except for a bomb blast near a polling station in a Muslim-majority province in the restive south, which injured three soldiers.

Election Commissioner Prapun Naigowit said the official election results would be announced on Wednesday.

Unofficial results were already coming in late yesterday.

The EC said it had tallied 34 complaints of election fraud, most of them related to giving money to voters. There seemed to be fewer grouses compared to December's general election, when the EC received more than 100 complaints.

According to the EC, nationwide voter turnout was estimated at 57 per cent of 44 million eligible voters, which was close to the turnout in last year's Constitution referendum.

The election agency earlier projected that between 60 per cent and 70 per cent of voters would exercise their balloting right throughout the country.

Deputy Prime Minister and Finance Minister Surapong Suebwonglee said it was a pity that fewer voters had exercised their right because the Senate election was significant for the democratic system.

The low turnout was attributed to people becoming bored with elections after having just gone to the polling booths on Dec 23.

Many voters also complained of having little knowledge about candidates' backgrounds and that not many candidates had contested the polls because each province would have only one senator, noted the minister.

Under the new Constitution, a total of 76 candidates will be elected - one for each province, including Bangkok. They will be seated in the uppper chamber, joining 74 senators appointed earlier by a selection panel and already endorsed by the EC. A senator serves for a six-year term.

The Senate has the power to remove Cabinet members, to appoint and remove the commissioners of independent state organisations and to approve laws passed by the Lower House. It has no right to propose a legislation, but can propose amendments to Bills.

XINHUA, ASSOCIATED PRESS