FREDERICTON - The leader of New Brunswick's New Democrats is calling for a ban on shale gas development in the province until a cost and benefit analysis is done.

Dominic Cardy says a ban would be more effective than a moratorium because it could only be lifted by a vote of the legislature, rather than a secret vote of cabinet.

Despite the demand, Cardy says he doesn't believe any of the gas companies could prove that benefits would outweigh the costs to the province.

His comments come in advance of the opening of the fall session of the legislature on Wednesday.

The provincial New Democrats have no elected members in the province.

Opponents to shale gas development are planning to protest outside the legislature on Wednesday prior to the delivery of the throne speech.