Downing Street said adoption rates for children in long-term care fluctuated significantly between different local authorities.
The spokesman said: 'The prime minister is signalling he intends to get involved in the issue and take it forward. We are certainly signalling national guidelines are one of the issues we have to address.
'Real hurdles are being put in the way of couples who want to adopt. There is work to be done by the department of health and the home office. We want to see whether new adoption laws are required.'
Mr Blair's spokesman accused some social services deaprtments of being 'lukewarm' about adoption.
'Part of the argument that's put is that the existing law tends to favour birth parents, to whom courts will prefer to give the benefit of the doubt even where there is a history of neglect or abuse.'
Mr Blair will head an inquiry committee that will incude Jack Straw, home secretary, Alan Milburn, health secretary, and Paul Murphy, Welsh secretary.
The committee is expected to look at the 'financial disincentives' to local authorities of arranging adoptions. At present, local authorities who place children with adoptive parents found by a different local authority or agency have to pay around£12,000 in 'transfer fees'.