UPFA MPs Bandula Gunawardena and Sisira Jayakody filed two Special Determination Petitions against the VAT (Amendment) Bill which was presented to Parliament and placed on order paper on October 4.
Through these petitions they argue that the bill is unconstitutional and needs a two thirds majority in Parliament and a referendum to be approved in its present form.
They challenge the provisions provided in the bill to levy taxes on healthcare and telecommunications sector.
A similar petition was filed by MP Udaya Gammanpila on Wednesday.