A disproportionate number of Muslims are being arrested under anti-terror laws compared to the number convicted according to a new report.

The Institution of Race Relations study published on Friday found that, of the suspects found guilty under the legislation introduced three years ago, most are non-Muslim.

However most of those arrested have been Muslim, fuelling fears of discrimination in the wake of the September 11 attacks on New York and Washington which prompted the tightening of the law.

Liberal Democrat MP David Chidgey, a member of parliament's joint committee on human rights, said it was logical that Islamic groups were targeted but feared the process was faulty.

"If that logic continued... you would expect most of those found guilty to be Muslim," he said.

"Either there is something unsafe about the way suspects are identified and arrested, or we may be missing those involved in other terrorist activities."

A Home Office spokesman said: "The issue of disproportionality is something we are looking at."

Just three of the 15 people convicted under the laws, which allow detention without trial, are known to be Muslim, and two of them have been granted leave to appeal.

But two thirds of a sample of the 609 arrests made using the Act were Muslim.

The IRR claimed that the public were being given the wrong impression over the effectiveness of the law.

"Since arrests under anti-terrorist laws attract widespread media coverage while convictions of non-Muslims in court have not been widely reported, most people are left with the impression that the criminal justice system is successfully prosecuting Muslim terrorists in Britain," the report concluded.

"The reality is that large numbers of innocent Muslims are being arrested, questioned and released while the majority of those convicted... are non-Muslim."