Jami-Lee Ross and three Auckland businessmen have pleaded not guilty to charges related to two $100,000 donations paid to the National Party in 2017 and in 2018.
National leader Simon Bridges told Morning Report Zheng Shijia, also known as Colin Zheng, was going to go to candidate college but he did not know if Zheng actually attended.
"My sense is that he was going to go to, but I don't know that he in fact did," Bridges said.
When asked for detail Bridges said it would be inappropriate to comment further.
"You're asking me questions that are tied up in a court case, and I think out of respect for the courts and that process it's just not appropriate for me to be casting light on things in relation to that."
Asked if it was credible that he and the party knew nothing at a time when Jami-Lee Ross was the party's chief whip, Bridges repeated his previous advice.
"No one in the National Party has done anything wrong, whether that's members of Parliament, the board, staff members or office holders within the National Party I know that to be the case."
Bridges said if he was called as a witness in the court case he would "obviously fully cooperate".