Dutch right wing populist party FvD leader Thierry Baudet | Bart Maat/AFP via Getty Images Expelled Dutch far-right lawmaker hits out at leader Thierry Baudet Forum for Democracy has become a ‘fan club’ for party chief, says ex-treasurer.

A Dutch senator who was kicked out of the far-right Forum for Democracy party over fraud allegations rounded on party leader Thierry Baudet, saying he treated colleagues "very badly."

Henk Otten, one of the founders of the party and a former treasurer, said Thursday that he was taking legal action over his dismissal.

"Baudet and I wanted to innovate, only Baudet turned too far right," said Otten, who on Wednesday was accused by the party leadership of "attempted fraud" with government subsidies and expelled from the party.

"I have kept silent for the sake of party interest, but that is now done," Otten told local media in response the accusations. He also said other party members were considering leaving. Baudet "treats people very badly, and pay attention to my words: many people are fed up with it, and feel offended. Everyone is at his mercy. It has become a sort of sectarian Thierry Baudet fan club now."

"Since the unsubstantiated claims of the board seriously damage my good name and reputation, I will report today to the Amsterdam police Thierry Baudet, Rob Rooken and Paul Frentrop for libel," he said. Rooken is one of the party's three MEPs, while Frentrop also sits in the upper house.

Forum for Democracy unexpectedly won the most votes in provincial elections in March and has two seats in the national parliament and 12 seats in the upper house (including Otten's) despite only being formed three years ago.

Otten has been under fire since April when he gave an interview to the NRC newspaper in which he was highly critical of Baudet and the way he was moving the party to the right. Shortly after that interview, the same newspaper reported that Otten had paid himself €30,000 without the approval of other board members. He was stripped of his role as treasurer and board member as a result.

Otten said he will keep his seat in the upper house but sit as an independent, which means the liberal party of Prime Minister Mark Rutte is now the biggest party in the Dutch Senate with 12 seats.