The mayor of a Romanian city has outraged Jewish and pro-democracy groups after he goose-stepped with his son in World War Two German uniforms during a weekend fashion show.

Wearing Nazi uniform is illegal in Romania, which denied participating in the Holocaust until 2004 when it accepted the findings of international commission that Romanian authorities killed up to 380,000 Jews in territories under their control.

The Center for Monitoring and Combating Anti-Semitism sent a letter on Monday to the country's general prosecutor urging an investigation of Radu Mazare, 41, mayor of Black Sea city port Constanta, for breaking the law and instigating a child to follow his example.

Mazare said the uniform had no swastikas and was the uniform of a German infantry general and nothing to do with the SS.

"I was inspired from the Valkyrie movie ... I wanted to dress like a Vehrmacht general because I've always liked this uniform, and admired the rigorous organisation of the German army," newspaper Evenimentul Zilei quoted him as saying.

Under pro-Nazi Marshal Ian Antonescu, Romania became a German ally in 1940 but switched sides just before war ended.