One of the men charged over donations to the National Party was at one stage to have gone to the party's candidate college, which identifies and train potential members of Parliament.
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".
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Govt failing to provide comprehensive coronavirus plan
Bridges said the government lacks a comprehensive plan to deal with the economic fallout from the coronavirus outbreak.
New Zealand's top-50 index closed down 1-percent yesterday and exporters, tourism operators and education providers have been hard hit by Covid-19 and the subsequent travel restrictions.
Bridges told Morning Report the economy should have been in a stronger position to begin with.
"[Finance Minister] Grant Robertson says the fundamentals are good, yes they're okay, they could have been better if it wasn't for the tax, the cost, the red tape and the uncertainty that this government has piled on.
"We're now faced with ... a very uncertain set of events, primarily around coronavirus but actually the droughts in New Zealand's a very significant issue as well and what I'm suggesting is what New Zealand needs is not just sector by sector relief, but that comprehensive plan that National has for New Zealand."
Australia's deportation policy
A National government will look at amending the law to allow Australians convicted of serious crimes in New Zealand to be deported because "fair's fair", Bridges said.
"I think the point I have been trying to make is we're great mates, but fair's fair and if they do it to us, we've got to think about what's in our interests and it seems to me it is absolutely in our interest to have a situation that's somewhat similar to what the Australians do on their side of the ditch."
Earlier this week Bridges said, if elected, National would explore a policy based on amendments to Australia's Migration Act in 2014 which allows for people to have their visas cancelled on character grounds.