David Blunkett is being urged to bring forward plans to allow phone-tapping evidence in UK courts so trials of foreign terror suspects can go ahead.
The UN expressed concerns about conditions at Belmarsh
It follows a plea by the UN Committee Against Torture that the government should review its policy of detaining foreign terror suspects without trial.
Eleven suspects are held at UK prisons under anti-terror legislation.
Liberal Democrat home affairs spokesman Mark Oaten said a change in the law could speed up the trial process.
He also called on the home secretary to take notice of the recommendations of the UN's report.
Mr Oaten said: "The home secretary should take serious note of this report and bring forward plans to allow phone evidence to be used in court so Belmarsh
detainees can be tried."
Foreign terror suspects have been held without charge at London's Belmarsh and other prisons for up to three years under legislation introduced following the September 11 attacks.
The Anti-Terrorism, Crime and Security Act 2001 allows the home secretary to detain without trial foreign nationals he suspects of terrorism.
But there has been widespread condemnation by human rights activists, who say the practice is akin to mental torture.
Of the 17 Islamist terrorist suspects detained under the law, 11 remain in custody.
In many of the cases, it is believed information against the suspects has been gathered by phone-tapping - but such evidence is not currently admissible in UK courts.
Mr Blunkett told ITV1's Jonathan Dimbleby programme last week he was considering allowing wire tap evidence in criminal trials as part of more far-reaching measures to tackle terrorism.
He said the proposals included special anti-terror courts without juries.
However, he said any new legislation would wait until after the next general election.
Under the Anti-Terrorism, Crime and Security Act (ATCSA), the home secretary can indefinitely detain, without charge, a foreign terrorist suspect
Seventeen men are being held under the anti-terror measures - mostly at Belmarsh
A team of psychologists have claimed eight men detained in Belmarsh without charge are suffering a deterioration in mental health
New anti-terror laws would also see the introduction of trials without jury and the use of phone-tap evidence
Over the past two weeks, the UN committee has been quizzing UK officials on compliance with the 20-year-old Convention Against Torture.
The committee also expressed concern at conditions in south London high-security jail Belmarsh where suspects have been held indefinitely.
The UN urged the government to "review, as a matter of urgency, the
alternatives available to indefinite detention".
As well as anti-terrorism policy, committee members also looked at the issue of evidence gained though torture.
It urged the UK to close legal loopholes which allow evidence obtained by
torture in another country to be used in British courts.
Civil rights group Liberty spokesman Barry Hugill said he hoped the British government would now "be honest about they are doing" in accepting evidence obtained under torture.
Evidence obtained under torture was "useless because when people are tortured they will - for very obvious reasons - say absolutely anything", he said.
Mr Hugill said foreign nationals suspected of terrorism in the UK "should be treated in the same way as a British national suspected of terrorism here".
Committee members expressed concern at the "limited acceptance of the applicability of the convention to the actions of its forces abroad".
The committee also said the results of inquiries into the alleged misconduct of UK soldiers during the conflicts in Iraq and Afghanistan should be published.