More research into the causes of excessive drinking is needed before the government takes tougher action, health minister Dawn Primarolo has said.

She was responding to a report by the Nuffield Council on Bioethics which said increasing alcohol tax and restricting hours of sales could help tackle a rising number of alcohol-related deaths.

The report criticised the government's strategy of using publicity campaigns and voluntary labelling schemes, saying they are ineffective, and called for an urgent study into the effects of 24-hour licensing.

But Primarolo, appearing on BBC Breakfast, said the causes of excessive drinking were "complex", and added that only about one per cent of pubs had increased their hours since liberalisation in 2005.

She said the Department of Health was looking into the effects of heavily discounted alcohol on sale in supermarkets.

"When we look at the cost of alcohol, and particularly tax on it, we have something like the second highest level in Europe," she said.

"The issue is discounted sales, and the Department of Health is already progressing research that is looking at that whole area of using discounted sales to get people to buy more."

Asked if discounting could be banned, she said: "I think we need to firstly make clear what is actually the cause of people increasing drinking.

"And actually the problem if you like is particularly acute in middle-aged middle class drinkers.

"We are working to get the evidence to see if action is needed there."

She added: "We're looking at where it's available, who it's available to, how it's being marketed, what the targeting is and what we can do to give clear messages and to make those who are selling it responsible."

Nuffield's report said the number of deaths due to alcohol-related medical conditions doubled from just over 4,000 in 1991 to more than 8,000 in 2005.

The report comes as a coalition of 21 organisations headed by the Royal College of Physicians also formed the Alcohol Health Alliance.

The group will lobby for a 10 per cent increase in drink taxes, which it estimates would cut alcohol-related deaths by between 10 and 30 per cent.

Amid media reports of a new "crackdown", a Number 10 source told Tuesday's Daily Mirror: "There are serious concerns, not just about when alcohol is sold, but about how it's priced, how it's advertised and who it's sold to."