Eight per cent of single parents in Britain are fathers.
The announcement will give hope to campaign groups that have argued for years that fathers deserve a legal right to more equal access after a divorce.
It will also overturn the main finding of an independent official review into family justice by David Norgrove, which reported in November. He concluded that it would be too onerous for judges to ensure greater equality of access.
Ministers are bracing themselves for a backlash from single mothers’ groups that are concerned about the possibility of aggressive fathers intervening in the lives of their children.
The working group, comprising education ministers Tim Loughton and Sarah Teather, and justice minister Jonathan Djanogly, has been asked to come up with proposals on how the law should be changed within two months.
Campaign group Fathers4Justice claims that every day 200 children lose contact with their fathers because of decisions taken in family courts. Under the plans the 1989 Act could be amended to include a “presumption of shared parenting”, this newspaper has learnt.
Mr Loughton last night told The Daily Telegraph: “The state cannot create happy families, or broker amicable break-ups.
“But if children are having decent, loving parents pushed out of their lives, we owe it to them to change the system that lets this happen.”
One official said the Government wanted to remove any “inbuilt legal bias against the father or the mother” in the law. The official said: “This is about the children. Both parents should have a full and continuing role in a child’s life after they separate.
“Where there are no significant welfare issues, we would want to see this principle reinforced through law. We will make a legislative statement emphasising the importance of children having an ongoing relationship with both their parents at separation, when it is safe and in the child’s best interests.
Mr Norgrove originally proposed a right to equal access in law for both parents last March and then dropped it from his final 220-page report in November.
He said it would put too much pressure on judges to set out the exact length of time that each divorced parent should spend with their children.
Mr Norgrove, who chairs the Low Pay Commission, cited evidence from Australia which suggested children suffered more when courts imposed time limits on access to parents.
Mr Loughton, who had campaigned to change the law when in opposition, suggested Mr Norgrove had read too much into the Australian example.
He added: “The concept of 'shared parenting’ after a break-up often gets confused with the idea of equal time that a child spends with each parent.
“Quite clearly, ordinary living and working arrangements make an equal division impossible, and undesirable, in all but a small minority of cases.
“In all of this, the most important thing remains the principle that the child’s welfare is the paramount consideration and this must not be diluted.”
Ministers are also set to announce a £10million fund to encourage more parents to use mediation. Mr Loughton added: “The courts are rarely the best place for resolving private disputes about the care of children.”