A committee of MPs has said that the maximum period terrorist suspects can be held without charge will have to rise beyond 28 days.

In a report released on Monday, the Commons home affairs select committee said that the powers available to the police and security services would need to increase in line with the escalated threat of attack.

On the recommendation of the police the government failed in a bid to raise the period from 14 to 90 days last year, settling on a compromise of 28 after being defeated by its own MPs

The committee said it had seen no evidence that a longer period would have been justified by any recent cases, but that it was almost inevitable that it would be required eventually.

"The growing number of cases and the increase in suspects monitored by the police and security services make it entirely possible, and perhaps increasingly likely, that there will be cases that do provide that justification," the report said.

"We therefore believe that the 28-day limit may well prove inadequate in the future."

However it added that greater civil liberties safeguards would also be needed to balance the police's greater powers.

And while the committee concluded that a greater period of time would be needed, it criticised ministers' attempts to introduce one, saying they had not properly examined the police's case.

"On such a major issue, with very significant human rights implications, we would have expected the case made by the police to have been better developed," the committee said.

"The police should have been able to present an evidence-based analysis of the type we have endeavoured to undertake.

"It is clear that this was not done, despite their reliance on their 'professional judgment'.

"We think it is reasonable for the prime minister and home secretary to rely on advice from the police on such issues, but we would also expect them to have challenged critically that advice in order to assure themselves of the case that was being made. We heard no evidence that this had happened: this is unsatisfactory."

Neither was the committee report unanimous with Labour member David Winnick, who introduced the 28-day amendment, saying that the case for any increase on that had not been made and that any such move would anger the Muslim community.

But the government has indicated that it would have liked to increase the limit further, with chancellor Gordon Brown signalling at the weekend that a revival of the 90-day proposal could be part of his likely future premiership.

The Home Office welcomed the report, saying the recommendations would be considered carefully.

"The proposed legislation was discussed extensively with stakeholders, including the Opposition," a spokesman said.

"The strong advice we received from the police, most notably from the country's most senior anti-terrorist police officer, was that terrorist investigations are now more complex and that the current maximum period of detention - 14 days - was no longer considered adequate.

"Based on operational experience, the police concluded that there was a need to hold a small number of terrorist suspects for up to a maximum of 90 days in order to continue investigations before charging them with a specific offence.

"All extensions to detention are subject to judicial oversight. Following lengthy debate, parliament approved a maximum period of detention of 28 days."