TAIPEI (Jan 2):'' Taiwan stocks ended down 1.69 percent on the first trading day of the new year on Monday, weighed by heavyweights such as TSMC, with investors cautious ahead of the island's presidential election and with little guidance as most regional markets are closed.

The main TAIEX index shed 119.87 points to 6,952.21, its worst one-day percentage fall since Dec. 19 and extending the 21 percent fall for the whole of 2011.

Electronics slipped 1.47 percent, with the world's top contact chip maker TSMC 1.06 percent lower. The biggest losing sector was financials, down 2.96 percent.

"Trading will continue to be quiet and upside will be limited due to the uncertainty and risk associated with the outcome of the elections," said Tu Jin-lung, chairman of Grand Cathay Investment Advisory. "The best scenario before the vote is that the National Financial Stabilization Fund would support the market at the 7,000 point level."

The state fund, which has a mandate to stabilise markets during strong volatility, began stepping in last month as the benchmark index declined.

Taiwan holds presidential elections on Jan 14 in a vote that will determine whether the island deepens economic integration with mainland China or embarks on a period of more tense and possibly fractious cross-Strait relations.

The Taiwan dollar weakened slightly to trade at T$30.326. Foreign investors were net buyers on Friday, bringing their total buying to T$39.38 billion in December.- Reuters