Taxes on high-strength beers and lagers will be increased next year in an attempt to reduce problem drinking, the government announced today.

Beer stronger than 7.5% alcohol by volume will be subject to the higher duty from autumn 2011, while tax on low alcohol beers with a strength of 2.8% or less will be reduced. The level of increased taxation will not be revealed until the chancellor's spring budget. A spokesman for the prime minister, David Cameron, would not comment on its size, but said it would be large enough to influence drinkers' behaviour. The decisions on the strength levels at which the new duties will be applied reflected research by health and homelessness groups about the problems associated with super-strength lager.

The announcement comes ahead of today's publication of the public health white paper. The coalition is expected to pledge to improve the health of vulnerable groups such as the homeless, sex workers and prisoners by providing them with better NHS care.

The health secretary, Andrew Lansley, is setting up a health inclusion board to tackle chronic health problems among marginalised groups, many of whom often do not visit GPs, hospitals or dentists.

He has recruited one of the UK's leading doctors, Prof Steve Field, who until two weeks ago was chair of the Royal College of GPs, to lead the new body of expert advisers. Its members - doctors, nurses, charities and specialist in reducing health inequalities - will assess whether the NHS is doing enough to increase access to services for such groups and reduce the gaps between their quality of health and that of other members of the population.

The move is part of a new approach to tackle health inequalities, which did not improve under the last Labour government. More comprehensive details will be unveiled when Lansley publishes a white paper on public health.

"It's a scandal that life expectancy among homeless people is in the low 40s," said Field. "At a time when healthcare and lifestyle improvements mean that men and women are living longer than ever, some homeless people only live for about half the time average Britons do." Although some local NHS services do provide specialist care for the homeless, Field added, "It's appalling that the NHS has failed to deliver consistently good services across the country for disadvantaged groups. We want to ensure that all members of society, whether they live in Kensington or are homeless, receive the benefits of our ever-improving NHS."

Lansley admitted at the weekend that state intervention is sometimes necessary to protect people from themselves. The white paper's measures includes both "nudges" designed to encourage people to make healthier choices and changes in the law.

"We need a new approach to public health, one that directly involves the many influences on our choices," it says. "Too many people die too young, spending too long suffering from preventable ill-health, such as through alcohol abuse. The failures of policy to date are clear to see, as we have 1.6 million people dependent on alcohol."

The Downing Street spokesman said: "The objective is to encourage the production and consumption of lower-strength, rather than higher-strength beers. Clearly, tax is one of the instruments by which we can create incentives for production and consumption to change. The intention is to incentivise people to make different choices."

On Sunday, Lansley said that while he was not keen on regulation, "we have tried a lot of things and we do need occasionally to intervene. But more than that we need to support people. Especially some of the poorest in our society need to have the greatest support because health inequalities are too wide. We need to deliver improvements in the health of the poorest in this country the fastest."