President Xi Jinping says "earth-shaking changes" have taken place in relations between China and Australia as he signed off on his historic state visit.

Prime Minister Tony Abbott has described Mr Xi's visit as among "the most remarkable days of my life" during their final meeting of the trip on Wednesday at the Australia-China State and Provincial Leaders Forum in Sydney.

Mr Xi departs after signing a free trade agreement that axes tariffs in the resources and agricultural sectors and becoming just the second Chinese leader to address the federal parliament.

"My personal experience has given me the impression that earth-shaking changes have taken place in this relationship," he said after being feted across the country, from the G20 summit in Brisbane to his trips to Sydney, Hobart and Canberra.

"What we have achieved is unimaginable back over two decades ago."

Mr Abbott was fulsome in his praise for the Chinese leader.

"I have personally felt very privileged these last few days to have spent so much time with President Xi, and to have felt so much warmth personally," he said.

"These have been some of the most remarkable days of my life.

"The transition of China from the third world to the first world... is a transformation unparalleled in human history."

Mr Xi earlier on Wednesday told Mr Baird that Sydney was the last stop on his trip, because NSW was the biggest state in Australia, and to "highlight its importance".

It is the third time he has visited Sydney.

Mr Xi said he first visited Australia in 1988 while working as an official with the Fujian Province and he had a lot of personal experience.

"I firmly believe that we need to further promote relations at the state and provincial level," he said.

Mr Xi's father, Xi Zhongxun, signed in 1979 the first official Australia-China sister-state relationship, between the region of Guangdong and NSW.

As Mr Xi met with leaders at a hotel in Sydney's CBD, yellow-clad activists outside called for an end to the persecution of followers of the Falun Gong spiritual movement.

They were outnumbered by those in the pro-China camp, who banged drums and waved large Chinese flags.

Banners from both factions lined the street outside the Four Seasons Hotel, which was barricaded and watched over by a heavy police presence.