"We hold serious concerns about Dr Yang's health and conditions," Foreign Minister Penny Wong said in a statement.

"We continue to press to ensure his needs are met and he receives appropriate medical care."

Yang, a Chinese-born Australian citizen, has been in jail in China since 2019 on charges of spying, which he has denied.

Canberra reacted angrily to his sentencing in February 2024, expressing its "outrage" at the time.

Australia wants to see Yang reunited with his family, the foreign minister said.

"The Australian Government has made clear to China that we remain appalled by Dr Yang's suspended death sentence," she said.

"Dr Yang is entitled to basic standards of justice, procedural fairness and humane treatment, in accordance with international norms and China's legal obligations."

China on Wednesday insisted it was "governed by the rule of law" and asked Australia to "respect" its judicial sovereignty.

"China... fully protects the legitimate rights of relevant parties, and fully respects and protects Australia's consular rights such as visits," the foreign ministry said in a statement.

Yang's family said last year the father-of-two's health had deteriorated, as a cyst was growing on his kidney.

Australian officials say they understand his suspended death sentence may be commuted to life imprisonment if no "serious crimes" are committed for two years.

"The past year, and the five years of detention before his sentencing, have been a difficult and dark time for Dr Yang," Wong said.

"Throughout, he has demonstrated his inner strength and remarkable resilience."