CHENNAI (Reuters) - Millions of Indians voted in the final stage of India's closely fought general election on Wednesday, with signs that a weak coalition could emerge the winner just as the Asian power faces an economic
slowdown.

The left-of-centre Congress-led alliance is battling for re-election against a grouping led by the Hindu-nationalist Bharatiya Janata Party (BJP) and a third front of regional and communist parties. The outcome will be known on Saturday.

Indian elections are notoriously hard to predict, but most polls tip Congress as the likely victor. Nonetheless, the
pro-business BJP is seen as having gained late traction with some savvy alliance building.

Either party may have to depend on the parliamentary support of an unstable coalition of regional parties and the
communists.

That scenario that could slow key reforms, such as relaxing labour laws, and rock investor confidence in an economy that faces a huge fiscal deficit.

The possibility of a hung parliament could mean the election is decided by backroom deals in the weeks after the
election, perhaps leading to a short-lived and unstable government.

Indian shares fell 0.5 percent on Wednesday afternoon on profit-taking. Shares had rallied 4.1 percent in Tuesday's
closing session on speculation the BJP would form the next government, traders said.

A clue to which party may take power lies with Tamil Nadu, the southern swing state in the 2004 election swept by Congress ally Dravida Munnetra Kazhagam (DMK) and which now rules the state.

Congress this time has lost allies in the state, one of the biggest prizes in the national battle with 39 seats.

The party faces the resurgence of the AIADMK party, led by former film star J. Jayalalithaa, a likely powerbroker after the polls.

Part of the Congress' problem in Tamil Nadu is voter backlash against rising prices and power cuts.

"The Congress will suffer because of the DMK's unpopularity," said political commentator Cho S. Ramaswamy.

The BJP has no major ally in Tamil Nadu but could be supported by any of the two state parties if it is seen in a
position to form a coalition government.

Jayalalithaa is now part of a third front of parties spearheaded by the communists. In the past she has helped both
Congress and the BJP form central coalitions.

Wednesday's vote was being held in nine provinces, including in the eastern West Bengal state where the ruling
communist alliance helped swing the last election in 2004 when its support gave Congress a majority in parliament.

But the communists, who quit the coalition last year angry at a nuclear deal with Washington and ruled out supporting a Congress-led government again, are expected to suffer poll losses because of their farmland acquisition policy.

"People will vote to save their land and livelihood, which means the communists will have a tough time," said Nepal
Haldar, a farmer in Kalicharanpur village of West Bengal.