Protesters have caused multiple disruptions during an address in Sydney from China's ambassador to Australia, Xiao Qian.

The ambassador, appointed earlier this year, had began speaking about how to improve ties between the two countries when he was interrupted by successive protesters.

One protester described Mr Xiao as a "representative of a dictatorship" and accused the Chinese government of committing genocide against the Uyghur Muslims in Xinjiang.

He was ushered out by security guards.

One man was asked to leave the venue prior to the event because he was dressed in a Cultural Revolution-era military costume that security described as "confronting".

Another protester held a sign reading "Free Tibet".

Yet another was escorted out after standing up and criticising China's censorship, saying people in Hong Kong and Tibet were unable to express their views freely.

The speech was widely seen as an attempt to thaw frosty relations between the two countries, in the wake of trade sanctions and a recent "dangerous" encounter between a Chinese fighter jet and Australian maritime surveillance aircraft over the South China Sea.

"How we can keep the momentum, and get our relationship back on the right track," Mr Xiao told the audience.

"This relationship is mutually beneficial in nature," he said, saying the "policy of friendly cooperation" remained unchanged.

But he added that in recent years the relationship had been "difficult".

"There are undeniably certain areas where China and Australia have different views. These are the areas where we should continue to conduct constructive dialogue."

More to come.