"We must press ahead with both economic structural reform and political structural reform, in particular reform in the leadership system of our party and country," Wen told reporters, adding it was an "urgent task."

"Without a successful political structural reform, it is impossible for us to fully institute economic structural reform and the gains we have made in this area may be lost," he said.

"New problems that have cropped up in China's society will not be fundamentally resolved, and such historical tragedy as the Cultural Revolution may happen again."

A visibly emotional Wen made the remarks at a news conference marking the end of the annual session of parliament -- the last of his 10-year tenure, which is drawing to a close.

Wen -- considered the most progressive of China's top nine leaders -- has mentioned the need for political reform in one-party, authoritarian China before, but these are his strongest comments yet on the subject.

In March last year -- at the same press conference -- he called for "gradual" political reform under the "leadership of the (Communist) party", and he made similar comments in 2010.

However, political analysts have in the past downplayed the significance of Wen's comments, saying he may be paying lip service to reform and democracy.