Former European commission head Jose Manuel Barroso on Tuesday accused Brussels of discrimination after it ordered an ethics probe into his new role at US investment bank Goldman Sachs.

"Not only are these actions discriminatory but they appear to be inconsistent with decisions taken in respect of other former members of the commission," Barroso said in a letter to Jean-Claude Juncker, his successor as commission president.

In addition to the probe, Juncker also said Barroso will now be received at the Commission, the executive arm of the 28-nation bloc, as a lobbyist rather than with the protocol given to a former president.