National MP Jami-Lee Ross is stepping down from the National Party front bench and taking leave from Parliament to deal with some personal health issues.
National Party leader Simon Bridges said the decision is not related to the investigation into the leak of his expenses.
"In recent days I have been talking with Jami-Lee Ross," Mr Bridges said.
"He has asked for some time away from Parliament to deal with some personal health issues and I have granted him that."
Mr Ross said in a statement he looks forward to returning to Parliament and re-joining Caucus in the future.
"Recently I have been dealing with some personal health issues," Mr Ross said in a statement.
"There are times in life where you have to put your own health and family first. As a husband and a father I need to do that at this time."
Mr Ross is an electorate MP for Botany in Auckland. A by-election will not be triggered unless he steps down from Parliament entirely.
Mr Ross' infrastructure portfolio will be picked up by Judith Collins, and his transport portfolio will be picked up by Paul Goldsmith. Paul Goldsmith's revenue portfolio will be handed to Andrew Bayly.
Simon Bridges: 'He's focusing on his wellbeing'
Mr Bridges said the National Party Caucus will be providing all the support it can.
Speaking from a press conference on Tuesday afternoon, Mr Bridges said Mr Ross will take a "few months" to focus on his wellbeing.
"My focus and Jami Lee's is to make sure he's getting the help he needs, he's focusing on his wellbeing and his young family at this time," Mr Bridges said.
Mr Bridges said the health issues could be "potentially embarrassing".
"Maybe that's not the right word. We all have our own views on these things… actually it's not really for me to characterise it," Mr Bridges said.
Mr Bridges said Mr Ross is "clear he's not the leaker", insisting the investigation is "entirely separate".