National MP Simon O'Connor says Judith Collins must resign after late night drama on Wednesday.
Collins released a statement at 9:30pm on Wednesday announcing the demotion of Simon Bridges over alleged inappropriate comments made several years ago.
It is understood the comments were made to Waitaki MP Jacqui Deans.
Bridges has labelled the move desperate and says it shows the lengths Collins will go to in order to keep leadership of the party.
O'Connor said has handed over his portfolios and says cannot work with Collins any longer.
"You cannot have a party where a leader is acting this way, against party members," he told Morning Report.