A verdict for writer Yang Hengjun has been delayed for a seventh time, now until April.
Senator Wong said Australia is "deeply troubled by the ongoing delays in his case".
"Our thoughts are with Dr Yang and his family," she said.
"The Australian government has called for basic standards of justice, procedural fairness and humane treatment to be afforded to Dr Yang, in accordance with international norms and China's legal obligations."
Senator Wong said the government will continue to advocate for Dr Yang's wellbeing at the highest level and provide consular assistance to him and his family.
The case against the writer has never been publicly disclosed and his trial was held in secret in May 2021.
Dr Yang has denied working as a spy.
Chinese ambassador to Australia Xiao Qian has said his government couldn't intervene in the cases as they were before the courts.
Consular officials were granted visits for Dr Yang and detained Australian journalist Cheng Lei, tried in secret on national security charges in March 2022, in early January for the first time since October.
with Reuters
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