The New Democrats are trying to temporarily ban bonuses for top executives and managers in the public sector.
The party is introducing a private member's bill that would eliminate performance pay and all forms of incentive pay for the next two years.
NDP Leader Andrea Horwath says the legislation would only apply to new contracts.
She said when almost all top civil servants are getting bonuses, it becomes a "below the radar" raise.
According to documents obtained under freedom of information laws, about 8,700 of 8,900 eligible managers received performance pay in 2011, costing the provincial treasury $35.6 million.
The bonuses ranged from 0.46 per cent of pay to 12 per cent. The average was 3.6 per cent.
The government has said bonuses are part of the pay package for managers, and are only awarded to those who meet their performance commitments.
Those who received a bonus had their salaries frozen, which has saved the province $34 million since 2009, the government said. The total cost of performance pay has also dropped 30 per cent — or $16 million — since 2009.