Greek police have swooped on fascist party Golden Dawn's offices after an anti-fascist activist was stabbed to death by a man involved with a neonazi street gang.

The 45-year-old admitted stabbing rapper Pavlos Fyssas, who identified his attacker to police moments before losing consciousness.

Witnesses said Mr Fyssas and his attacker had rowed while watching a football game at a cafe in western Athens.

The attacker later ambushed Mr Fyssas - who performed under the name Killah P - outside the cafe with a black-shirted mob clearly identifiable as members of Golden Dawn.

Golden Dawn originally denied any involvement with the attack, but callous MP Michalis Avranitis later admitted that the attacker had identified himself as a member.

"But Golden Dawn has one million supporters," he overestimated.

"If in a restaurant, two drunken idiots have a fight and someone is stabbed, should we look at their ideology and blame that?"

Public Order Minister Nikos Dendias of conservative New Democracy said he was "shaken" by the slaying.

He said recent violent incidents involving Golden Dawn, along with name-calling in Parliament, "shows in the clearest possible way the intentions of the neonazi creation."

But the Communist Party (KKE), whose own members were set upon in a "murderous" fascist attack last week, warned that the thuggish party had "support provided to it by the rotten capitalist system and the interests of big business."

Nine members of the KKE were hospitalised after being beaten with sharpened iron rods by Golden Dawn members on Friday.

All have since been released, but police have failed to take any concrete action against those responsible despite them being identified by the party.

Many took to the streets of Piraeus and Athens in protest at the killing, waving banners which declared the Golden Dawn party "fascist murderers."