The Environment and Rural Development Committee said that it was not in a position to judge whether a levy of 10p on every plastic bag would have a positive environmental impact.
Reports had suggested that the committee had gone cold on the idea, but its report on Tuesday said the levy remained a potentially powerful tool to cut plastic bag waste.
The vote has been delayed until the end of August 2006 to give Liberal Democrat MSP Mike Pringle, who lodged the Private Member’s Bill, time to provide more information.
Scottish Executive research raised concerns that the levy would lead to an increase in landfill waste if retailers switched to paper bags.
However, the committee had harsh words for the research and recommended a full review. Pringle said: “We are falling behind the times and need to address the environmental problems of plastic bags.”