TAIPEI (Reuters) - Taiwan's opposition presidential candidate retains a big lead ahead of upcoming elections, according to two opinion polls released on Monday, despite a historic summit between President Ma Ying-jeou and Chinese President Xi Jinping.

The breakthrough meeting on Saturday was the first by the leaders of the two sides since China's civil war ended in 1949, but it has stoked public debate over the island's ties with its giant neighbor in the lead-up to presidential and parliamentary elections in January.

The independence-leaning Democratic Progressive Party (DPP) has accused Ma of trying to revive the chances of his ruling Nationalist party, also known as the Kuomintang (KMT), in the elections with the surprise summit.

An opinion poll by Taiwan's Cross-Strait Policy Association on Sunday showed 48.6 percent of 1,014 people surveyed supported DPP leader and candidate Tsai Ing-wen while 21.4 percent backed KMT candidate Eric Chu.

That compared with support of 45.2 percent for Tsai in mid-October and 21.9 percent for Chu in an earlier poll by the association, which is comprised of prominent scholars and bipartisan figures.

"The Ma-Xi meeting wasn't aimed at interfering in Taiwan's elections. It is to set the tone for the cross-strait relationship in the post-Ma generation," Pang Chien-kuo, a member of the association, said at a news conference on Monday.

Tsai has been critical of the summit, saying she was disappointed Ma made no direct mention of Taiwan's freedoms and democracy.

In the poll taken on Sunday, 46.8 percent of those surveyed said they did not think Ma protected nor maintained Taiwan's sovereignty and interests in the meeting with Xi, while 32.9 percent said he did.

Taiwan, once ruled by a repressive KMT, evolved into an open and pluralistic society in the late 1980s with elections, a free media and a lively parliament, a contrast to mainland China where the Communist Party has retained a firm grip on power.

Chiang Kai-shek's Nationalists retreated to Taiwan after losing the civil war to the Communists. Beijing has never renounced the use of force to bring what it considers a breakaway province under its control.

A second poll of 1,330 people by a new group founded last month of bipartisan academics in Taiwan called the Justice Association found that 32.7 percent would vote for Tsai, while 21.1 backed Chu. The remainder gave their support to minority candidates or chose not to vote.

Ma's attempts to forge closer ties with China, mostly on the economic and trade front, have been greeted with some suspicion in Taiwan, with student protesters last year storming and occupying Taiwan's parliament for several weeks to demand the scrapping of a wide-ranging trade pact with China.

Xi said on Saturday that proponents of Taiwan independence must not split the two sides, a viewpoint since widely echoed in China's state media.

"If she takes office, Tsai will see her 'Taiwan Independence' policy responded to by powerful countermoves from the mainland," influential tabloid the Global Times, run by the Communist Party's official People's Daily, wrote in an editorial on Monday.

"The Xi-Ma meeting pushes forward the cross-Straits relationship and has been applauded globally. Yet Tsai, appearing wrathful, voiced harsh words that tried to belittle the meeting and exposed her support for 'Taiwan Independence.'"

Only the people of Taiwan can decide its future, Tsai said on Sunday.