"The governor of the province of North West Frontier Province may not assent to the Hasba (accountability) bill in its present form," the Supreme Court said in its order.

A provincial bill must be approved by the provincial governor, who is appointed by Islamabad, before it can become law.

The nine-member bench noted that many of the provisions in the bill violate the country's 1973 constitution.

The court had sat for four days to hear a challenge by the federal government against the legislation.

The issue was referred to the Supreme Court by President Pervez Musharraf, a key Western ally who has vowed to rid society of extremism.

The NWFP government said it had accepted the ruling by the country's highest court.

"We will bring the law again to (provincial legislative) assembly with certain amendments in the light of the Supreme Court verdict," senior minister in NWFP government, Sirajul Haq, told AFP.

"Our journey towards Islamic system in the province will continue," the minister said.

The bill authorised the provincial government to appoint a cleric called a "mohtasib (accountability officer)" to enforce a strict adherence to Islamic or Sharia laws.