National Party leader Judith Collins does not believe there is more to come out in the Nick Smith story. 

The veteran MP is resigning after revealing he's under an employment investigation for a verbal altercation last July.

Collins says she has been briefed that a staff member shouted at Smith, and he shouted back.

Pressed by The Country's Jamie Mackay if there is more to it than that, Collins says that she believes Smith was just ready to retire. 

"I don't know what's in the report. Ultimately, I think Nick Smith's got opportunities in life... and I think he wants to move on after 30 years of petty behaviour we see from time to time." 

Asked about Australian Prime Minister Scott Morrison's visit, Collins says that she got along better with him than Prime Minister Jacinda Ardern did, and that there is a bigger problem with China than the leaders admitted. 

She says that she told Morrison and every Ambassador who is asked about our relationship that China is the only major economy who has given us a free trade deal. 

"The best way for people to deal with us and have more choices around trade is for the UK and US to give us free trade agreements.

"Treat us like we really are equals, and then strangely enough we will be in a better position to diversify our export market."

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