Mr Porritt was defiant yesterday, insisting he was right to support a Plaid Cymru candidate in last June's European Parliament elections instead of the Greens' choice. He may be expelled in October.
As well as suspending Mr Porritt, the 30-member regional council - one of two key party committees - has ordered the Plaid Cymru MP Cynog Dafis to stop styling himself Plaid Cymru/Green. He is the nearest thing the Greens have to an MP.
The two decisions are likely to provoke a row at the Greens' conference in Hastings next month and face opposition from the party's 11- strong executive.
Mr Dafis was elected to Parliament in 1992 with the enthusiastic backing of the local Green Party in his Ceredigion and Pembroke North constituency.
Since then he has continued to work closely with the Greens at Westminster and in Wales and has tried to push through two environmental Bills.
But some Welsh Green Party members are unhappy at the flourishing alliance between the two parties locally as well as Mr Porritt's stance on tactical voting. Leading the opposition are Molly Scott and Dr Chris Busby, the two Welsh members of the Greens' regional council. Dr Busby was the Greens' official candidate in the Mid- and West-Wales Euro constituency - the man Mr Porritt declined to support in June.
Mr Porritt will have a chance to defend himself when the regional council next meets in October.
He said: 'I intend to do everything in my power to promote that 'real world' view of politics today. I would like to think I can continue to do it as a member of the party. If I cannot, too bad.'Reuse content