Transport for NSW has stood down a frontline employee after he attended a neo-Nazi rally outside Parliament House.

One of the men dressed in all black with black sunglasses on was identified as Sydney Trains employee Cooper Stephens by The Sydney Morning Herald this morning.

Sydney Trains said it was "very concerned with the matter" and has taken action against Stephens.

"In the interim, Sydney Trains has directed the employee not to attend work while the matter is examined," Sydney Trains said in a statement this afternoon.

"The employee's role is frontline and his actions are not supported by Sydney Trains or Transport for NSW and are not in line with public sector values."

Dozens of black-clad members of the neo-Nazi group National Socialist Network stood outside Parliament

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