Outcomes-based NHS targets are to be introduced as part of a focus on public health, Mr Lansley said at the Faculty of Public Health's meeting in London this month.
He later told GP that practices could expect to play a key role in meeting these targets.
Many of the outcomes GP commissioning will target would have 'significant public health implications', he said.
'GPs are our principal public health resource. If they are going to deliver commissioning outcomes, for many GPs, the way in which they will do it is to prioritise prevention, rather than simply to respond in terms of treatment.'
FPH president Professor Lindsey Davies said practices have a crucial role to play in helping patients stay healthy.
'Helping patients not to be ill is just as vital a role as treating them when they're ill,' she said. 'It will save work, but it will also make their patients happier and healthier.'
Mr Lansley said outcomes would need to be based on local solutions and areas would be given 'health premiums' to help them meet targets. 'We will not be dictating the "how" when it comes to achieving better public health outcomes. But we will be very clear about the "what" - what we want to measure and achieve,' he said.
The outcomes to be assessed will be subject to consultation. But he said they could include increases in life expectancy, improved immunisation rates and higher take-up of physical activity.
Mr Lansley also revealed that public health would receive a ringfenced budget, although he was unable to confirm its size.
He said the funding showed health inequalities could be tackled, even 'in the teeth of the debt crisis'.