Health Minister Shona Robison will today visit one of the pilot areas which tested banning off-sales to under-21s, as the consultation into the government's controversial package of measures to tackle alcohol abuse ends.

It has been suggested that ministers are preparing the ground to water down the proposals, but a senior government aide insisted last night that where such schemes had resulted in reduction in antisocial behaviour they had a duty to consider them.

Ms Robison will visit Stenhousemuir today to meet senior police officers and the proprietor of an off-licence to discuss the pilot scheme there raising the age for such alcohol purchases from 18 to 21 at weekends.

The Coalition Against Raising the Drinking Age in Scotland claimed the "true results" of such trials showed "raising the minimum purchase age for alcohol will not help solve Scotland's alcohol problem".

The campaign, which includes the National Union of Students and the Scottish Youth Parliament, claimed in a submission that while the average number of vandalism incidents and calls about youth disorder had fallen, the average number of minor assaults had actually risen during the pilot project.

Tom French, the campaign coordinator, said: "If the police have conceded, based on the actual results, that these trials were inconclusive, and the official analysis shows this to be the case, it beggars belief that the Scottish Government are still peddling mistruths in some attempt to hold together their increasingly shaky case for raising the minimum purchase age."

Tory community safety spokesman John Lamont said: "The key is to target problem drinks and problem drinkers and a crackdown using existing laws to punish those who sell to under-age drinkers. The SNP's blanket approach simply does not do that."

A Scottish Government spokeswoman said: "We welcome all engagement with the consultation process, because alcohol misuse costs Scotland at least £2.25bn every year. "