The regional administration is drafting new laws to ban the use of polythene for promotional purposes and impose heavy fines on people.
"This is the first step towards a polythene free province," Udaya Gammanpila, environmental minister of the western provincial council told reporters.
Sri Lanka has provincial councils, which can pass their own local laws as well as charge separate sales taxes.
Officials are hoping to bring a law out within two months.
"The intention of this statute is to stop the use of different kinds of polythenes in decorations and also for the purpose of trade promotions such as banners, cutouts and posters," Jagath Gunawardena, a lawyer who is an environmental activist said.
"The fine will be up to 50 000 rupees or a term of imprisonment up to 3 years or both the fine and imprisonment the court deed with it," Gunawardena said.
Polythene is now heavily used in elections and political rallies to decorate the roadside.
"I did not use polythene for my electio