The British government is on Wednesday to announce minimum alcohol pricing in a bid to curb "drunken mayhem" on the streets of England and Wales.

The coalition is set to unveil a consultation on setting a minimum price of 45 pence per unit of alcohol sold, 5 pence higher than Prime Minister David Cameron backed earlier this year.

Scotland has already proposed a price of 50 pence for a unit.

Home Secretary Theresa May will explain the plans as part of efforts to "turn the tide" on irresponsible drinking.

Supermarket "buy one, get one free" offers are also expected to be banned.

Home Office officials stressed that the consultation was targeted at "harmful drinkers, problems pubs and irresponsible shops", not those "who enjoy a quiet drink or two".

The Alcohol Health Alliance (AHA), made up of 32 medical and counselling organisations, welcomed the step but chairman Ian Gilmore called for tougher measures.

"The evidence shows us that heavy drinkers and young drinkers are more affected by higher alcohol prices than moderate drinkers," he said.

"According to the University of Sheffield, a minimum unit price of 50 pence would reduce total alcohol consumption by 6.7 percent, saving around 20,000 hospital admissions in the first year."