The MLCs say they will block all legislation unless the state government takes action against environmental activists and campaigns that the forest industry claims is damaging their business.

Every MLC except for the two Labor members - Derwent MLC Craig Farrell and Hobart MLC Doug Parkinson - and independent Rosevears MLC Kerry Finch, are supporting the unusual step, which is to be formally announced this afternoon.

This will effectly put an end to hopes that additional national parks could be established in Tasmania and would mean no regional development funding would be available.

MORE TO COME