British prime minister David Cameron said he wants to cut welfare for people under the age of 25 and for families with more than three children, in an appeal to his Conservative Party base amid tensions with coalition partners.

Mr Cameron used a speech in southeast England today to set out ideas for overhauling the welfare system, some of which he acknowledged wouldn't be acceptable to the Liberal Democrats, the junior member in his Conservative-led government.

He said he was setting his aim beyond the next election in 2015.

"We have, in some ways, created a welfare gap in this country - between those living long term in the welfare system and those outside it," Mr Cameron said.

"Those within it grow up with a series of expectations: you can have a home of your own, the state will support you whatever decisions you make, you will always be able to take out no matter what you put in."

The move allows Mr Cameron to offer voters an idea of the goals he'd pursue if the Conservatives governed alone, as well as shore up support among Tories who are angry at the compromises made with the Liberal Democrats since the coalition took office two years ago.

Mr Cameron said the current system reduces incentives to work and is causing resentment.

Other signs of a distinctive policy from the government emerged last week when Conservative Education Secretary Michael Gove proposed replacing the current general certificate of secondary education exams, taken at age 16, and returning to "O-Levels," abolished in 1988.

That was attacked by deputy prime minister Nick Clegg, the Liberal Democrat leader, as a move to "turn the clock back to the past."

Bloomberg