Tong said he and Zhang were concerned with the way Ross had been making his allegations.
"Whatever this chap Ross is going on about, he needs to step up and say exactly what did occur," Tong said.
"There are going to be people hurt in the bloody meantime, that's the trouble."
"I don't want my name associated with anything Jami Ross has done."
According to a Stuff report, Tong said Zhang had also told him he didn't make the donation at the centre of the scandal.
"Zhang is not the alleged donor of the funds," Tong said.
Tong also told media outlet Newshub that he believed Zhang had no connection to the matter.
"It's not about [Zhang], it's about the relationship between Mr Ross and Mr Bridges," he said.
"I have 100 per cent confidence Mr Zhang is not involved in this matter."
"This needs to come from Jami-Lee Ross or the police or Paula Bennett, they're the ones who can establish the facts."
Ross thrust Zhang into the national spotlight earlier this week with his claims that a $100,000 donation from businessman had been split into smaller chunks so its origins could be hidden.
He told reporters that he did not believe Zhang was guilty of any wrong doing and had simply been caught up in Bridges' alleged plan to circumvent campaign funding rules.
Ross - in an extraordinary press conference - said: "On the 14th of May this year I attended a dinner with Simon Bridges at the home of a wealthy Chinese businessman."
He later named Zhang and then tweeted pictures of Bridges and Zhang at the dinner.
Bridges denied any breach of the law and accused Ross of lashing out after being exposed as the likely source of an information leak to the media.
