Paul Ryan has been ordered to stay at home after allegedly impersonating Hitler while on duty.
Mr Ryan, a Police Community Support Officer working for the Safer Neighbourhoods Team in Swiss Cottage, north London, is being investigated by the Metropolitan Police after complaints about his behaviour.
The alleged incident happened last month at the unit's base in Finchley Road when Mr Ryan began goose-stepping around the office and making Nazi salutes during a conversation about Germans, police sources said.
The PCSO was previously removed from Kentish Town Safer Neighbourhoods Team for suggesting to a black colleague that there was nothing wrong in voting for the far-right British National Party, it is understood.
A spokesman for Camden police said Mr Ryan was suspended on August 5 after an allegation of misconduct at work on July 24.
He said: "The alleged incident occurred in police premises not accessible to the public. All such allegations are taken very seriously and an internal investigation has been launched.
"It would be inappropriate to comment any further at this stage."
Mark Gardener, spokesman for the Community Security Trust, a charity guarding against anti-semitism in the UK, said the Met was right to take tough action.
Mr Gardener said: "Obviously we would thank the police for their prompt action and voice extreme concern at the suitability of this police officer.
"This kind of action would cause offence, not only to Jewish people, but many others as well.
"We would be extremely concerned at any police officer making fun of Nazism."
But Trudy Gold, chief executive of the London Jewish Cultural Centre, urged caution and said that dismissing the PCSO as a racist could be political correctness gone mad.
She said: "If it was meant as humour it is probably in bad taste but is Monty Python funny? Is Mel Brooks funny when he does the dancing and singing Hitlers in The Producers?
"It comes down to the question of whether we can make fun of evil. It is a difficult area but I wouldn't want to condemn him as evil for making a Hitler salute until we know the context - if he is a card-carrying member of the BNP, for example."