The Chinese Foreign Ministry said on Monday that China has lodged stern representations with Australia over "inappropriate" comments by former Australian Prime Minister Tony Abbott about Taiwan.

Abbott last week visited Taiwan, which is claimed by China, in a personal capacity, met Taiwanese President Tsai Ing-wen, and told a security forum that China may lash out with its economy slowing and finances "creaking."

"The relevant words and actions by the Australian politician go against the 'One China' principle and send a seriously wrong signal," Zhao Lijian, a spokesman at the Chinese Foreign Ministry, told a regular media briefing. "China is firmly opposed to this. We have made stern representations to Australia."

China's Embassy in Australia on Saturday called Abbott a "pitiful" politician after his visit to the self-ruled island.

"Tony Abbott is a failed and pitiful politician. His recent despicable and insane performance in Taiwan fully exposed his hideous anti-China features. This will only further discredit him," it said in a brief statement on its website.

Abbott's visit came after China carried out four days of mass air force incursions into Taiwan's air defense identification zone beginning Oct. 1.

Australia, like most countries, has no official diplomatic ties with Taiwan, but has joined its ally the United States in expressing concern at Chinese pressure, especially military.

Taiwan says it is an independent country and will defend itself if China

Australian Prime Minister Scott Morrison said earlier that Abbott in was Taiwan as a private citizen.

"I didn't have any conversation with him before that. Tony has served as my envoy to India. We went to India. We spoke, but Tony is there as a private citizen. So what he's said and what messages he passed, he passed on in that capacity."