John Keells Holdings has not asked for a tax holiday for gaming revenues, he said.
De Silva said even if a license was issued under existing laws if an administration headed by the opposition United National Party comes to power, the tax holidays would be reversed.
The proposed casinos are included in larger 'integrated resorts' involving hotels, shopping and entertainment complexes.
"We are not opposed to tax holidays for the hotel," de Silva said.
"We are only opposing the taxes for casino revenues."
United National Party legislator Harsha de Silva said it was unconscionable that Sri Lanka which had among the highest food taxes in the world has made casinos tax free.
The reason many Asian nations allowed casinos was simply to get taxes for the state, with Macau being the most successful with no income tax but gaming revenue taxes at 40 percent.
Other countries had income tax but lower levels of around 20 percent on gross gaming revenues and value added taxes.
But Sr