By Harry Papachristou

ATHENS (Reuters) - Greece suspended several senior police officers on Monday and launched an investigation into possible police links with a far-right party, after the killing of an anti-racism rapper raised concerns about the force.

Pavlos Fissas's stabbing by a Golden Dawn supporter last week revived accusations that police were turning a blind eye to the party's activities or had even been infiltrated by it.

A man who said he had a "loose" connection with Golden Dawn has been charged with Fissas's murder but the party, Greece's third most popular, has denied involvement.

The investigation comes as Prime Minister Antonis Samaras's government tries to rein in a party that has surged in popularity during Greece's economic crisis. With its vehemently anti-immigrant rhetoric, Golden Dawn is often blamed for attacks against immigrants, something it denies.

The public order ministry ordered the investigation after media reports alleged police were "actively involved" with the party's activities and may have participated in illegal acts.

Five senior national police officials as well as the police chiefs in the Athens neighborhoods of Nikaia and of Keratsini, where the killing occurred, have been transferred and will be replaced, the police said in a statement.

"The minister is determined to dispel any shadow of doubt that hangs over the force," the statement said.

Four police officials in Evia in central Greece were suspended on Monday for failing to investigate why people had been found carrying weapons, including baseball bats, near Golden Dawn offices in the area, the public order ministry said.

Two other high-ranking police officials also resigned, citing personal reasons, it added.

DIRTY WAR

Calls to ban Golden Dawn have increased in recent days, and the leftist opposition Syriza party has accused the government and the police of failing to investigate allegations that the party's cells were operating within the force.

"They thought (Golden Dawn) was a little snake and they patted it," Syriza leader Alexis Tsipras said. "Now it's about to choke us."

Police have often refused to investigate racist attacks by Golden Dawn members on immigrants, newspaper Eleftherotypia reported on Monday, citing a leader of the Pakistani community in Athens.

The party, with an emblem resembling a swastika, denies accusations of violence. Its members have been seen giving Nazi-style salutes but the party rejects the neo-Nazi label.

Golden Dawn rose from being a fringe party to win 18 parliamentary seats in a June 2012 election. But support fell by 2.5 percentage points after the stabbing and most Greeks believe it threatens democracy, a poll showed on Monday.

The poll, conducted on September 19-21, put support for Golden Dawn at 5.8 percent, down from 8.3 percent on September 15.

When asked to described the party, 47 percent of those polled called it a "fascist organization", 31 percent called it a "criminal organization under the guise of a political party", and 16.9 percent saw it as a "populist nationalist movement".

Golden Dawn lawmaker Ilias Kasidiaris told reporters: "The media, the parties and the government are waging a dirty war on us. We won't stop. We have the law and one million Greeks on our side."

(Additional reporting by Karolina Tagaris; Writing by Deepa Babington; Editing by Kevin Liffey and Robin Pomeroy)