BRUSSELS — A top European Union official raised concerns Tuesday over the potential influence of a former president of the bloc’s executive arm on negotiations related to Britain’s exit from the EU, following his summer appointment at Goldman Sachs.

Jose Manuel Barroso, who served two terms as European Commission president through late-2014, joined Goldman Sachs in July in a move that revived complaints about EU officials taking up lucrative jobs after leaving.

Barroso is understood to be advising the U.S. bank on issues related to so-called Brexit.

EU Ombudsman Emily O’Reilly, who oversees transparency issues, said in a statement that “this is a significant public interest issue and must be openly and comprehensively addressed.”

In a letter to the current Commission president, Jean-Claude Juncker, attached to the statement, O’Reilly said “public unease will be exacerbated by the fact that Mr Barroso has publicly stated that he will be advising on the U.K.’s decision to leave the EU.” Britain narrowly voted in June to leave the EU but discussions on how that will happen have yet to formally start.

The Commission’s Brexit team is led by French politician Michel Barnier, who was commissioner for internal markets and services during Barroso’s second five-year term. O’Reilly wants to know whether Barnier and other staff have received orders on how to “engage” with Barroso.

Though Barroso respected the mandatory 18-month cooling-off period before joining Goldman Sachs, his appointment has drawn widespread criticism. Britain’s Guardian newspaper has reported that more than 75,000 people have signed an EU staff petition calling on Barroso to forfeit his EU pension over the move.

Goldman Sachs is particularly toxic for some as the bank has been accused for misleading investors about the quality of its loans ahead of the 2008 financial crisis. Goldman is also alleged to have helped the Greek government hide details about its national debt for more than a decade.

In July, Juncker told French media that “the fact that the former president works for a bank does not pose a problem. But for that one, that one poses a problem for me. You must carefully choose your employer.”

Commission spokesman Alexander Winterstein said Tuesday that any meeting between Barroso and officials would be noted on the EU executive’s public register.