A committee of MPs has warned that government reform plans could make it harder to remove failed asylum seekers.

Under the Asylum and Immigration Bill, announced in the Queen's Speech, families who refuse a free flight home will have their benefits withdrawn.

Ministers say that to prevent the children from suffering as a result of this decision, they would be taken into care under clause seven of the legislation.

But in a report published on Monday the Labour-dominated home affairs select committee argued that such a move would drive asylum seekers underground, and could even act as an "incentive" for families to disappear, leaving their children in the care of the state.

The MPs also expressed concern that the government could not give estimated numbers of children who would be taken into care under the change.

Members of the committee concluded that the legislation should not come into effect until assurances were given that the move will not lead to significant numbers of children being taken into care

Ministers should report to parliament once a year on how many families have had their benefits withdrawn and how many children have been taken into care as a result, added the report.

Home Office minister Beverley Hughes defended the policy and noted that the committee had "welcomed in principle our measures to withdraw family support from those who have no right to be here".

"The government faces difficult choices in ensuring that a fair and effective system results in those whose claims are refused actually leaving the UK," she said.

"At every stage, either a voluntary or enforced return home will be pursued. Ending support would be a last resort.

"However, we do not accept that this gives parents an incentive to abscond and if we thought there was a substantial risk of this we would consider detaining families."

Launching the report, former Home Office minister John Denham attacked his old ministry for failing to provide sufficient information about its plans.

Denham, now chairman of the committee, said that the Bill could not be adequately scrutinised because of time constraints.

He also warned that interested parties could not comment because of a lack of detail.

"We understand the government's desire to press ahead with further changes to the asylum system," he said.

"However, it has not been possible for us, in the time available, to scrutinise all the measures in the Bill.

"Nor was sufficient detail provided in the government's consultation document to enable concerned organisations to respond in detail.

"There is a strong case for many measures included in the Bill, but it is important that parliament also ensures that they can and will be implemented effectively, efficiently and fairly."

The Conservatives welcomed the report's emphasis on making rapid asylum decisions.

"We agree that it is the decision-making process that needs speeding up, not just the appeals process," said shadow home secretary David Davis.

"The removals process must also be reformed - it is unacceptable that under Labour asylum seekers have a ninety per cent chance of remaining in this country. The government must categorically state that it will not use the children of asylum seekers as pawns in their presentational power play."

Davis added that under Labour the asylum system had become "a complete shambles".

"Last year more asylum seekers came to Britain than any other country in the world," he said.

"Labour have made Britain a magnet for migrants seeking to abuse the asylum system and for unscrupulous people traffickers.

"They must not be allowed to use the crisis they created as an excuse for legislation that is in parts ill thought through and in others bordering on draconian."