He said party members had told him the decision had been taken at a party central committee meeting on March 27.
Weerawansa said the party had decided to cancel his membership after provincial council polls planned for the eastern region next month.
He also said the JVP had originally decided to field him in some of the rallies planned for the polls.
Party insiders say the current turmoil over Weerawansa was triggered by differences in his stance over a breakaway Tamil Tiger group in the East of the island carrying arms.
Earlier reports had said that the party's central committee has voted to replace Weerawansa as its parliamentary group leader.
Weerawansa is a charismatic public speaker who helped popularize the concept of 'removing the plug' or insulating Sri Lanka from world market prices with go