Gloria Arroyo had said a coup was being planned

President Gloria Arroyo invoked the order, saying there was a plot against the government.

The court said the proclamation was legal but that certain police and army actions had been unconstitutional.

The chief justice said those who drew up the measure were "playing with fire" and had to be "prudently restrained".

The government's decree had expanded the powers of the military and police, allowed rallies to be banned and permitted arrest without warrants.

The Supreme Court said calling on the military to end lawless violence was legal but other actions were "unconstitutional".

They included the arrest of certain protesters and a labour leader; a raid on an opposition newspaper; and threats to media freedom.

'Nuclear teeth'

Chief Justice Artemio Panganiban said the emergency measure had "nuclear teeth that must indeed be defanged".

He said: "Some of those who drafted proclamation 1017 may be testing the outer limits of presidential prerogatives.

"They are playing with fire and, unless prudently restrained, they may one day wittingly or unwittingly burn down the country."

President Arroyo said the emergency measures were necessary to defend her government against a coup plot by rogue soldiers, communists and some politicians.

But opposition groups who filed petitions against the order said the state of emergency infringed civil liberties.

Mrs Arroyo imposed the order on 24 February, just before planned protests to mark the 20th anniversary of the uprising that forced former President Ferdinand Marcos from office.