The most revealing moments of Xiao Qian's Press Club address make clear why Australia's relationship with China is so strained

It's 18 years since a Chinese ambassador last took up an invitation to appear at the National Press Club in Canberra.

Once the questions began, however, it became very clear just how uncompromising China would be on the core issues causing such difficulty in the relationship, particularly the big one — Taiwan.

The change of government in Australia raised some hope of a relationship reset.

At the Press Club podium in Canberra, Xiao defended the show of military might, saying Pelosi's visit had "compelled" China to respond.

Once that happened, Xiao said: "There might be a process for the people in Taiwan to have a correct understanding of China about the motherland.".

On the detention of Australian citizens Cheng Lei and Yang Hengjun, China's ambassador insisted "their basic rights are protected, so don't worry about that".

On the trade sanctions China has imposed on Australian exports, the ambassador preferred not to call them "sanctions", but he did signal some willingness to negotiate their removal, as long as Australia was willing to overturn its ban on Huawei.

The differences over Taiwan, trade, the detention of Australian citizens and Putin's actions in Ukraine are deep.

Back in 2004, the last Chinese ambassador to address the Press Club, Fu Ying, raised Beijing's concerns about any move towards independence in Taiwan, but wasn't talking about departing from the status quo.