Long-serving NSW MP Fred Nile has sacked four board members from his Christian Democratic Party and suspended others as he struggles to keep his troubled party intact.

In an unprecedented move, the Reverend Nile, 85, has written to the party's board telling them he had decided to sack the board members and suspend his former parliamentary colleague Paul Green.

Fred Nile and his teenage tormentor, Samraat Grewal. Credit:Jon Reid, Facebook

Mr Green was an upper house Christian Democratic MP from 2011 until this year's March election but failed to be re-elected, leaving Mr Nile as the party's only representative in the NSW Parliament.

Mr Nile said his decision was necessary to "resolve the turmoil amongst board members" and he had used "his authority as founder" of the party to take the extreme steps.