Jami-Lee Ross has made further allegations against Simon Bridges by implying he was involved in the Chinese community's attempts to have a Chinese minister appointed.
The National leader said in statement he has full confidence in his MPs.
Ross was part of the Justice Select Committee that heard submissions on Thursday from Security Intelligence Service (SIS) boss Rebecca Kitteridge and the Government Security Communications Bureau's (GCSB's) Andrew Hampton.
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Ross, an independent MP who resigned from National last year, asked Kitteridge whether the SIS had ever raised concerns in briefings to ministers or the leader of the opposition, Simon Bridges, over "specific individuals" posing a threat to New Zealand politics.
She responded: "You're asking a hypothetical question. But what I can say, is that in this area we've provided briefings to - as we required to do - to both ministers and the leader of the opposition across this area of concern."
Ross then asked Kitteridge a question related to comments he said Bridges made on May 14 last year, following an event where discussions centred on a desire by the Chinese community to have a MP appointed in a future government.
He said the National leader told him he couldn't go through with it though, alleging Bridges told him: "I can't do it because basically the spooks [spy agencies] are telling me he's a Chinese spy."
Ross asked Kitteridge if Bridges had based his comments on intelligence from the SIS. But Kitteridge told Ross she could not comment on intelligence provided.
"I can't speak for the leader of the opposition about what he intended in any conversation that he had, but the other thing is that we don't report publicly on the intelligence we provide to ministers or the leader of the opposition," Kitteridge said.
Bridges said in a statement on Thursday: "I don't disclose briefings I may or may not get on national security. I have full confidence in all of my MPs. They are all here working in the best interests of New Zealand."
The Ross-Bridges saga
Last month, police referred a complaint to the Serious Fraud Office about donations made to National.
Police said the complaint, made in October last year, was in relation to the disclosure of political donations under the Electoral Act.
Last year, Ross alleged Bridges had committed electoral fraud by asking him to split up a $100,000 donation from Chinese businessman Zhang Yikun into smaller amounts, so they could be hidden from the Electoral Commission.
The now-independent Botany MP released a recorded phone conversation between him and Bridges, where the former National MP could be heard asking his then-leader what to do with the $100,000 donation.
Ross told media last month the funds, before it entered National Party accounts, arrived in amounts smaller than the $15,000 disclosure threshold. He said the $100,000 donation "was offered by the donor directly to Simon [Bridges] on the 21st May".
"It was after that contact with Simon at a National Party event in the Epsom electorate that he then phoned me and asked me to initiate contact with the donor," Ross alleged.
Bridges defended himself at the time, saying: "I've got nothing that concerns me about any of this... I don't think National MPs have anything to worry about. We have nothing to hide. We do want to see swift justice here."
China has been pointed to as a potential threat to New Zealand's democratic processes. The New Zealand Defence Force last year explicitly named China as a threat that challenged international governance values.
National MP Dr Jian Yang sparked concerns in 2017 after he admitted training Chinese spies so they could monitor other countries' communications - but refused to say whether this included New Zealand.
He denied ever being a spy or having intelligence training, but admitted teaching students English to help them with their spying activities.
During the select committee on Thursday, Kitteridge spoke about the threat of foreign interference in New Zealand, particularly around foreign powers influencing elections.
She said interference in New Zealand elections by a state actor "was, and remains, plausible".