It confirmed Gardner remained in custody and had legal representation.
Consular staff were providing him advice and checking in on him.
The ministry has remained in regular contact with Gardner's family, but said it could not "comment on or intervene in the judicial proceedings of another country".
In a live television broadcast of the court proceedings yesterday, Gardner was heard testifying off-screen that he had made "a really big mistake" and brought "a big shame" to his family.
"I'm really sorry, I really regret it ... I have broken the law and there's no getting out of it."
Gardner has said he would be willing to co-operate by identifying Chinese drug traffickers, and that he had no drug convictions in Australia or New Zealand.
Gardner's Australian girlfriend, Kalynda Davis, was travelling with him at the time and was also detained.
She was released in December without charge.
Gardner's former boss Michael Kulakovski, earlier told media he was surprised to hear of the charges, saying Gardner was a "great guy".