"This is a very important visit. ... This delegation's visit will be a reciprocation of two visits paid by North Korean state delegations to China," foreign ministry spokeswoman Zhang Qiyue said.
"It will be important in promoting the two countries' relations."
Wu, chairman of China's National People's Congress, will lead a delegation to the Stalinist state Wednesday where they are expected to discuss tensions over North Korea's nuclear drive and other bilateral issues.
The visit has long been anticipated and comes as hopes are rising that another round of six-nation talks in Beijing to resolve the year-long nuclear crisis could take place in the next two months.
A first round of talks involving the United States, China, Japan, Russia and the two Koreas ended in August without agreement.
North Korea however signalled a shift in stance Saturday when it said it was ready to consider President George W. Bush's offer of written security guarantees in return for scrapping its nuclear weapons programme.
Zhang Tuesday refused to say what Beijing hoped to gain from the visit, saying only that China was "actively" trying to help push for another round of discussions.
"We hope the Beijing six-party talks can be continued because we believe the only way to resolve this problem is through dialogue and peaceful means," Zhang said.
She said Wu will leave Beijing for Pyongyang Wednesday morning by plane and will be travelling with a large entourage.
Among those accompanying him are Vice Premier Zeng Peiyan, former head of the State Planning and Development Commission; Vice Foreign Minister Wang Yi, an old North Korean hand; deputy Minister of Commerce Yu Guangzhou; and Ge Zhenfeng, vice chief of the General Staff of the People's Liberation Army.
Zhang, however, refused to say who Wu will meet and whether he will be granted a audience with North Korean leader Kim Jong-Il.
Asked to confirm reports that the next round of talks could take place in December, Zhang declined to comment.
"Our hope is such kind of talk will take place as early as possible," she said.