More flexible leave for parents, father-friendly access arrangements following relationship breakups, faster adoption processes and better help for special needs pupils will be included in a new children and families bill, designed to be a central plank of government policy.

Focusing on the shakeup of family justice to deliver a "fairer" system for parents, ministers signalled that the government did not accept last year's family justice review, which warned against introducing a legal presumption of shared parenting. The review said such a move could create an "unacceptable risk of damage to children".

However, the Queen's speech includes a consultation on legal options to strengthen the law in England and Wales to ensure that, "where it is safe and in the child's best interests", both parents are able to have a relationship with their sons and daughters after they split up.

The bill also sets out plans to speed up adoption and care proceedings and give more support to disabled children. The bill will create a six-month time limit for family courts in England and Wales to reach decisions on whether children should be taken into care and will require the court to take into account the impact of delays on the child. Many social workers argue that they are unable to tackle delays in other parts of the system – such as family courts.

In another long-trailed announcement, the new bill will stop local authorities in England from delaying adoptions in the hope of finding a perfect racial match for the child, if there are couples waiting to adopt.

Martin Narey, the government's adoption adviser, said that the measure was needed as black children are three times less likely to be adopted than white children, despite Labour issuing guidance to local authorities in 2000 asking for no ethnic considerations to be made.

In most cases, the child's ethnic background and that of the prospective adopters should come second to efforts to place the child swiftly in a permanent home, the bill says. The government will discuss with Welsh ministers whether the change should be extended to Wales.

The bill also aims to give families more choice and control over support for children with special educational needs (SEN).

The system of SEN statements for children with disabilities and learning difficulties will be replaced in England from 2014 by a simpler assessment process providing statutory protection up to the age of 25 for those who go into further education, rather than it being cut off at 16. Young people will be given the right to a personal budget to buy support and care, marking another attempt to devolve responsibility to users of services.

The bill will also make the office of the children's commissioner, Maggie Atkinson, "more independent" from ministers and give it powers to carry out assessments of the impact of government policy on children.