The National Party has elected Judith Collins as its new leader to replace Todd Muller.

Collins, 61, was first elected as an MP for Clevedon in 2002 and has been part of six Parliaments.

The MP for Papakura has been the shadow Attorney General since May and holds the National party's spokesperson roles for several areas, including Economic Development, Regional Development and Pike River Re-Entry.

She has previously been the minister for ACC, Corrections, energy and resources, ethnic affairs, ethnic communities, justice, police, revenue and veterans' affairs.

According to her National Party profile, she holds a Bachelor of Laws, Master of Laws with Honours and a Master of Taxation Studies from the University of Auckland and was a lawyer and company director before being elected to parliament.

She replaces Todd Muller, who resigned this morning, saying it had become clear he was not the best person for the job.

"The role has taken a heavy toll on me personally, and on my family, and this has become untenable from a health perspective," he said.

Muller was elected as a new MP for the Bay of Plenty in 2014. He took over the leadership after rolling Simon Bridges in May.

His was a short leadership, lasting only 53 days.

Voting was still under way for a deputy as the news broke.

Collins' history with scandal or controversy:

  • Dirty Politics 2014: She was accused of leaking information to her friend and right-wing blogger Cameron Slater in the book Dirty Politics. She resigned from Cabinet after allegations she tried to undermine the Serious Fraud Office director. An inquiry cleared her of wrongdoing. She was reinstated in 2015.
  • Oravida 2014: She visited the Shanghai offices of Oravida, of which her husband is a director, while on a taxpayer-funded trip. The company used her photo as a product endorsement.
  • Wetlands comments 2014: It emerged swamp kauri had been stockpiled in Northland under the name Oravida Kauri, another business linked to Oravida and Ms Collins' husband. She outraged environmentalists by telling a reporter she did not care, saying, "Am I the Minister of Wetlands?"

More to come...