A tender had been called on 03 October 2016 to purchase the desks and chairs for Rs. 1930.
A technical evaluation committee has recommended the measure on a trial basis.
Coastal, rural and urban schools are to be introduced with plastic desks and chairs, according to its recommendations.
Plans are being made to introduce them for grade four and five classes.
A committee tasked with preparing a technical evaluation report has had three of its members removed with no reason, the unions allege.
The ex-members Dr. H.K.G. Punchihewa of Moratuwa University, A.P.R. de Silva of the Sri Lanka Institute of Engineers and M.A.R. Madhuwanthi of Government Works Department are technical experts.