Drug addicts receiving treatment should be given shopping vouchers to help them tackle their problem, an NHS body suggested today.

The National Institute for Health and Clinical Excellence (Nice) accepts that the idea is controversial but said it would be cost-effective.

International trials have shown modest financial incentives can help hardened addicts stay off drugs.

Nice said there would also be a public health benefit because addicts could also be screened for infectious diseases - such as HIV and tuberculosis.

Users could get vouchers worth up to £10 at NHS treatment programmes - if tests show they are free of drugs.

The proposal for an incentive scheme is contained in draft guidance on how the NHS in England and Wales should handle drug misuse.

The draft guidelines also consider how to give addicts information about self-help groups, such as Narcotics Anonymous, and how to best support families and carers.

A consultation on the proposals is open until early March, with full guidance due to be issued to the NHS in July.

Professor Peter Littlejohns, clinical and public health director at Nice, said: "The draft recommendations are based on the best available evidence on which psychosocial approaches work most effectively.

"A wide range of issues are covered by the draft guidance - the draft recommendations are not intended to be used in isolation but rather as a package of interventions to provide support for people trying to overcome their addiction.

"This draft guidance includes recommendations on incentive systems to encourage people misusing drugs to stay free from illicit substances, with proof provided by negative drugs tests.

"The guideline development group has made this recommendation based on evidence that this type of approach is effective, and providing incentives to encourage treatment attendance is reported to be effective in other healthcare fields."

A Department of Health (DH) spokesman said: "This is not final Nice guidance to the NHS. It is a draft guideline for consultation and will be developed further in response to the comments received as part of the consultation.

"The consultation is an important part of Nice's transparent process for producing guidance to the NHS and DH will be responding to it along with other stakeholders.

"Nice's current draft guideline makes a number of recommendations on the use of suitable privileges or rewards to encourage compliance with treatment regimes. This is one of a range of approaches that may support better outcomes. These are potentially important suggestions that warrant further discussion."

Martin Barnes, chief executive of charity DrugScope, broadly welcomed the proposals.

He said the benefits to society of effective drug treatment would outweigh the cost of an incentive scheme. But he stressed it must run alongside attempts to tackle the underlying reasons why people turn to drugs.

He said: "There is good evidence that the longer someone is engaged with drug treatment the better their outcome.

"The cost of vouchers will be modest compared to the benefits of more effective treatment.

"However, for treatment to be most effective the underlying factors contributing to problem drug use and relapses need to be tackled, not least decent housing, social support and routes to training and employment."