National Party leader Christopher Luxon will shortly speak in Parliament after MP Sam Uffindell was suspended from caucus pending an investigation into further "very concerning accusations" about his past behaviour.

Christopher Luxon told reporters before Question Time that his primary focus was on a high-quality, independent investigation.

"We have very serious allegations from a complainant who I have huge empathy for." On the other hand, he said, Sam Uffindell disputed these.

Asked if Uffindell still retained his confidence, Luxon said: "All I am saying is new and serious allegations came to light last night. I want to make sure they are investigated. I will reserve my judgment on that."

Luxon said overnight he had been made aware of new allegations about the Tauranga MP's behaviour towards a female flatmate while Uffindell was at university in 2003.

Uffindell has denied any accusations he was involved in bullying or intimidatory behaviour while at university.

This morning Luxon told Newstalk ZB's Mike Hosking the situation was very concerning.

"You got a situation where a young woman, a flatmate has made serious allegations. It is a concerning situation for a father whose daughter is flatting, it's very real. They are serious allegations that need to be investigated. Sam is disputing the allegations."

Asked if Uffindell still had his backing, Luxon told TVNZ: "We'll find out in the next few weeks because really, what this investigation is about, is looking at both sides of that investigation."

Luxon also acknowledged that the investigation was needed to honour the "alleged victim" too.

National Party president Sylvia Wood said the investigation into the latest allegations would be conducted by Maria Dew QC and is expected to take two weeks.

The new allegations came a day after revelations that the new Tauranga MP, as a teenager, beat up a younger boy at boarding school.

The revelations have also raised questions about National Party culture and selection process for MPs. In recent years several National MPs and candidates have been embroiled in controversy.

Luxon said he should have been informed earlier. The delegates should have been informed and the voters of Tauranga should have been informed earlier.

He said Uffindell's admission during selection had triggered deeper background checks and he believed that was how it was supposed to work.

Luxon said National's character checking extended to speaking to people who had known Uffindell since after the King's College beating.

After the press conference, Luxon will be up in the House where he has the first question to Prime Minister Jacinda Ardern.