China's ambassador lashes out at Australian politicians who have recently visited Taiwan, saying the MPs are being manipulated by separatist forces inside the self-governed territory.

Speaking in Sydney, China's ambassador Xiao Qian warned Australian parliamentarians should think carefully before travelling to the democratic island.

Mr Xiao said it was very important for Australian politicians to respect that Taiwan was part of China.

"Taiwan is a province of China. They need to respect that there's a commitment by the Australian government of [the] One China Policy and they need to respect the sentiments and the feelings of the 1.4 billion Chinese people," he said.

"I hope they will stick to the One China policy in words and in deed; refrain from engaging with Taiwan in whichever form of capacity so that you will not be politically utilised by people in the island with political motives."