However, Sir Liam disagreed with the prime minister's claim that heavy drinkers represented a minority.
He said: "I think these strong actions in public health are always controversial.
"The report has only just come out, and it needs to be debated and considered."
He said the evidence had shown that price and access were key determinants of drinking habits.
He said: "Any plan to combat a problem needs a backbone. Price and access are that backbone - I will continue to champion it.
"This is a key measure which would almost certainly make a major impact on our drink problem as a country."
Sir Liam's report said a 50p minimum price for a unit of alcohol would mean a standard bottle of wine could not be sold for less than £4.50, a two litre bottle of cider for £5.50, and the average six pack of lager for £6.00.
Sir Liam Donaldson defends his recommendations
The Chief Medical Officer estimated the measure would add around £1 a month to the drinks bill of a moderate drinker - but more for those heavy drinkers who were at risk.
He said after ten years such a move would lead to 3,400 fewer deaths and 100,000 fewer hospital admissions a year.
He also suggested minimum pricing would have a significant impact on crime rates.
But Prime Minister Gordon Brown said that he did not want to penalise "moderate" drinkers.
Speaking at a press conference at 10 Downing Street on Monday he said: "We don't want the responsible, sensible majority of moderate drinkers to have to pay more or suffer as a result of the excesses of a minority."
The Conservatives say it is important to deal with people's attitudes to drinking, not just supply and price, while the Liberal Democrats support putting an end to "pocket-money priced" alcohol.
Sir Liam's idea has the backing of Alcohol Concern, but the drinks industry's Portman Group believes it would have a marginal effect on harmful drinkers.
But Alan Maryon-Davis, president of the Faculty of Public Health, said the step could have a huge impact.
"These measures would not only benefit the population at large, but would target effectively the most vulnerable groups, the young binge-drinkers and older harmful drinkers."
The NHS bill for alcohol abuse is an estimated £2.7bn a year.
The most recent figures show hospital admissions linked to alcohol use have more than doubled in England since 1995.
The Scottish Government has already proposed minimum pricing.
Earlier this month SNP ministers put forward the suggestion to stop alcohol being sold a cut-price offers.
If the plans were adopted, Scotland would become the first country in Europe to take such a measure.
Both Wales and Northern Ireland have also expressed an interest in minimum pricing, while ministers in England have said they would not rule it out in the long-term.
Last year, research published by Sheffield University - and commissioned by the Department of Health - concluded increasing the price of alcohol would be one of the most effective measures to tackle alcohol abuse.
Petra Meier, one of the Sheffield team, said a 50p minimum price would lead to a cut of 7% in alcohol consumption across the board, and 10% cut among heavy drinkers.
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