Hundreds of Taiwanese opposition demonstrators stage protests outside a hotel in Taichung where negotiators from Taiwan and China met for a fourth round of trade talks Tuesday. (Wally Santana/Associated Press)

Negotiators from China and Taiwan met for a fourth round of trade talks Tuesday amid protests by critics who fear the Taiwanese government's China-friendly policies are opening the door to eventual unification with the mainland.

Officials plan to sign three minor agreements later in the day and discuss a free-trade deal that has fired up critics of President Ma Ying-jeou's push to link the export-dependant island's economy ever closer to China's.

Hundreds of protesters have gathered outside the hotel in the central Taiwanese city of Taichung where the meetings are taking place.

They are being held back by a strong police presence in an effort to prevent a reoccurrence of the violence that marred a previous meeting in the capital, Taipei, a year ago.

In their opening statements, the negotiators dwelt on the benefits of closer co-operation for both sides.

"Peaceful development between the two sides is the overwhelming trend. No one can stand in its way," Chinese delegation leader Chen Yunlin said.

Since taking office in May 2008, Harvard-educated Ma has moved to ease tensions with China. He has pushed a welter of business-boosting initiatives, including regular air and sea links with the mainland and ending across-the-board restrictions on Chinese investment in Taiwan.

Many in the main opposition Democratic Progressive Party believe Ma's China-friendly push is setting the stage for an eventual Chinese takeover of the island, which Ma vehemently denies.

China has made unifying with Taiwan — by force if necessary — the core of its Taiwan approach since the sides split amid civil war in 1949.

Ma has said repeatedly that unification is not on the cards during his presidency, which would last until 2016 if he's re-elected, and most Taiwanese take him at his word.

But some in his party favour unification, raising opposition fears that steps toward that end could still be taken while he's in office.

The DPP also fears that Ma's intended trade deal — formally known as the Economic Cooperation Framework Agreement — will flood the island with cheap Chinese products, prompting massive job losses.

Ma rejects that assertion, saying the trade deal is necessary to prevent Taiwan's economic marginalization amid growing commercial China and neighbouring Asian countries.

With files from The Associated Press