Labor has added its weight to federal government calls for detained Australian writer Yang Hengjun to be afforded basic legal rights by Chinese authorities.
Dr Yang will be tried on charges of espionage in a closed Chinese court next week after being held in Beijing for more than two years.
Foreign Minister Marise Payne says despite repeated requests by Australian officials, Chinese authorities have not provided any explanation or evidence for the charges he faces.
Since his detention the 55-year-old blogger has had no access to his family and limited access to his lawyer.
Prime Minister Scott Morrison says it is "absolutely untrue" Dr Yang acted as a spy for Australia, and Dr Yang has told his family he was innocent and would "never confess to something I haven't done".
Labor senator Penny Wong said on Saturday the opposition was deeply concerned that Chinese authorities had failed to provide any explanation or evidence for the charges.
"We strongly support the government's advocacy for Dr Yang, including through consular assistance, and are disappointed that he has not received basic standards of justice or procedural fairness consistent with China's international legal obligations," she said in a statement.
Senator Wong said China also had obligations under the Australia-China bilateral consular agreement.
As a result, Australian officials should be permitted access to Dr Yang's hearing on May 27 and he should be granted advanced access to his lawyer and consular officials in advance.
Dr Yang's trial had been due to start in January but has been delayed by four months.
He faces a lengthy jail sentence if found guilty on charges of endangering national security by joining or accepting a mission from an unidentified espionage organisation.
Dr Yang was detained by Chinese authorities in January 2019 at Guangzhou Airport after arriving from New York.
Australia has consistently lobbied in his support and that of a second detained Australian, journalist Cheng Lei, who has also been held on suspicion of endangering national security.