Senior state government ministers have rubbished claims by Opposition Leader Matthew Guy that he knew nothing about a substantial payout to a staffer over harassment allegations within his own ranks.

Fairfax Media on Sunday revealed that former Liberal MP Nick Kotsiras made the payout of just under $100,000 prior to resigning from Parliament in 2014.

Opposition Leader Matthew Guy Credit:AAP

HIs resignation paved the way for Mr Guy's move from the upper house to the lower house in the safe seat of Bulleen.

The secret payment to a young female staff member by the former government minister followed accusations of harassment in the months leading up to the previous state election.