A 5p tax on single-use carrier bags will be introduced in Northern Ireland next year.

The levy will double to 10p in 2014, when a 10p levy on the more durable multi-use shopping bags will also be brought in, Stormont Environment Minister Alex Attwood said.

Northern Ireland will become the second UK region to implement the environmental tax, following Wales's lead last year. A similar levy is also in effect in the Republic of Ireland.

Mr Attwood said he was setting the 5p rate in the first year to allow customers time to adjust to the concept. "There is no doubt that carrier bags are a scourge on the environment," said the SDLP minister.

"Evidence from other countries demonstrates that a bag levy is a simple and effective means to reduce substantially the negative environmental impact of carrier bag consumption. A proposed 10 pence levy on single use carrier bags and lower-cost reusable carrier bags can bring about significant environmental improvement.

"However I recognise that consumers will need time to change their behaviour and adjust to bringing their own bags when they shop. I therefore propose to discount the charge to five pence in the first year, when the levy will only apply to single-use carrier bags. This will ensure a phased approach to charging.

"I am committed to making Northern Ireland a better place to live, work and invest and this will certainly contribute to that goal."

But a body representing small retailers expressed concern about the move.

Glyn Roberts of the Northern Ireland Independent Retail Trade Association said: "We agree with the DOE Minister's objective of reducing plastic bag usage and our members have led the way in educating customers and pioneering voluntary approaches to addressing this problem.

"However, we are concerned that this is a tax on hard-pressed working families and will add to the burden of red tape, particularly for small shops, who will become tax collectors for this new scheme. It's unclear if it is intended to discourage plastic bag use or if it is a revenue raiser. It has to do one or the other - it can't do both."