David Cameron has promised targeted help for the most dysfunctional families and more support for couples in failing relationships.
Reaffirming his commitment to the family today, the Prime Minister signalled a new emphasis on promoting stable relationships between parents.
He acknowledged that some would advise the Government to "stay clear" of the issue.
But he insisted it was wrong to ignore something that affected children's life chances and led to many of the country's social problems.
"The whole country pays the price of failing relationships, so discussing the issue should be part of our politics," he said in a speech to Relate.
Mr Cameron announced that Government spending on relationship support would be increased from 5 million to 7.5 million a year.
Organisations such as Relate would also be allowed to use Government buildings for accommodation outside office hours.
The Prime Minister announced that up to 500 of the most troubled families would receive targeted support as part of a trialled approach to be run by entrepreneur Emma Harrison.
"What works is focused, personalised support - someone the family trusts coming into their home to help them improve their lives step-by-step, month-by-month," he said.
The Government would be providing funding for the scheme, designed to "get these families back into work and on their feet".
The Government believes about 120,000 struggling families need help with problems such as poor health, drug and alcohol addiction, unemployment and difficulties controlling their children.
More money is to be set aside for early intervention projects, and local authorities are to be allowed to pool budgets to work on new approaches to providing help.
"The seeds of so many social problems - as well as success stories - are sown in the early years," Mr Cameron said.
"Family is where people learn to be good citizens, to take responsibility, to live in harmony with others. Families are the building blocks of a strong, cohesive society."
He added: "When parents have bad relationships, their child is more likely to live in poverty, fail at school, end up in prison, be unemployed later in life.
"It would be wrong for public policy to ignore all this. No one who wants to tackle some of our deepest social problems - and the massive economic costs they bring - has a hope unless they understand the importance of family."
Mr Cameron praised the former Labour government's Sure Start centres but said they had concentrated too much on support for children and "shied away" from relationships between parents.
The Prime Minister also restated his commitment to introducing tax breaks for married couples - another point of conflict with the Tories' Liberal Democrat coalition partners.
"Of course, I know not everyone agrees with this proposal - and as part of the coalition agreement we have agreed with the Liberal Democrats that they will abstain on any budget resolutions on transferable tax allowances for married couples," he said.
"But my view remains that we should recognise and value the commitment that people make to one another.
"And by the way, that's whether it's between a man and a woman, a man and a man, or a woman and another woman."