Chinese President Xi Jinping on Tuesday met a former chairman of Taiwan's ruling Kuomintang (KMT) party who will attend Beijing's massive military parade this week despite opposition from Taipei.

Taiwan has condemned the visit of former vice president Lien Chan and encouraged its veterans to stay away from the parade celebrating the 70th anniversary of Japan's defeat, as Beijing and Taipei clash over who should take the credit for victory against Japan in 1945.

Forces of the KMT, then the rulers of China, fought all the major set-piece battles against Japan during a bitter eight-year war before allied forces intervened.

But China's Communist Party -- which defeated the KMT in a subsequent civil war and forced them to flee to Taiwan -- depicts itself as playing the leading role in defeating Japan.

Meeting Xi, Lien emphasised the KMT's role in the war effort.

"The Chinese KMT forces... fought a series of decisive and major battles on the front line and dealt the Japanese military a heavy blow," Lien told Xi, according to Shanghai news website guancha.cn.

"The Chinese Communist Party forces led by Mao Zedong effectively pinned down and intercepted the Japanese and the collaborationist militaries on the battlefield behind enemy lines," he added.

Xi, who is head of the Communist Party, said the KMT and the Communists "cooperated and coordinated" in the campaign and "both made significant contributions to the victory of the war against (Japanese aggression)", the official Xinhua news agency reported.

"Chinese people across the Taiwan Strait must keep history in mind, remember national heroes and get united to maintain the victory fruits and jointly advance the peaceful development of our relations," Xinhua quoted him as saying.

The office of Taiwan's president last week said that citizens should refrain from taking part in the parade, after a government spokesman warned against "distorting" history.

The military parade will feature 12,000 soldiers and 500 pieces of hardware rolling through Tiananmen Square with almost 200 aircraft flying overhead, in a display of strength as Beijing takes an increasingly assertive stance regionally.

China's army expansion has worried several of its Asian neighbours, and major Western leaders have shunned the show amid fears that Beijing is seeking to show off its military might.