Drug users will be able to get up to four times as many syringes than before when they visit needle exchanges.

The move announced by the Scottish Executive is aimed at preventing the spread of infections like HIV and hepatitis.

Addicts can now be given a maximum of 20 sets on their first visit, compared to five before, with a maximum of 60 on subsequent visits, up from 15.

Old needles and syringes have to be returned

They will also be given as many as 120 sets during holiday periods when facilities are closed or difficult to access.

The exchanges only happen when users return old needles and syringes for safe disposal.

Chief Medical Officer Dr Mac Armstrong said the changes will help stop the spread of bloodborne viruses.

"A sizeable proportion of those currently known to have HIV and hepatitis C have been, or still are, injecting drug misusers," he said.

"It is vital that we take every opportunity to reverse the rising trend of HIV and hepatitis C in our communities.

"One very effective way of doing this is to do all that we can to discourage those who continue to misuse drugs from sharing dirty injecting equipment.

Infection risk

"It is important to remember that these rising numbers are not only a threat to the individual who is infected and those close to them, but also increase the pool of infection within the wider community, hence making the risk of spreading infection greater.

"This revision has been made following consultation with representatives from the police, substance misuse agencies and the public health field.

"We are also making it clear that these increases are subject to the return of used equipment for safe disposal by exchange staff."

The move follows a consultation exercise and advice from the Lord Advocate.