The European Commission had been pressed for answers by MEPs furious at the circumstances in which Mr Juncker’s right-hand man Mr Selmayr landed the job of the Commission’s top civil servant.
Green MEP Sven Giegold was among those on the European Parliament’s Budget Control Committee (CONT) asking Mr Juncker why his protege had apparently been fast-tracked into his new job without any competition after the sudden retirement of predecessor Alexander Italiener.
In addition, the decision to promote Mr Selmayr twice in the space of a few minutes on the day his new job was announced has also rung alarm bells.
Writing yesterday, Mr Giegold said: “Just now the Coordinators of the CONT Committee have been informed that the Commission will not be meeting the deadline set for today 3pm to reply to our 130 questions regarding the appointment of Martin Selmayr as Secretary-General of the European Commission.
“A reply is expected to be send over the weekend.”
Mr Giegold said committee members had been informed in an email from the CONT secretariat that it was likely replies to the questionnaire would be sent over the weekend.
The committee is due to vote on the budget on Monday but Mr Giegold said the ballot should be postponed.
He said: “The discharge of Commission’s budget should be postponed from the Plenary in April to a later date (probably October) that allows for scrutiny of all documents that allow Parliament to fully understand.
“On Tuesday, 27th March the debate on the appointment of the Secretary-General of the European Commission will take place in an open hearing with Günther Oettinger.”
Mr Juncker will not attend this meeting after three blocks of MEPs – from the European People’s Party (EPP), the Progressive Alliance of Socialists and Democrats (S&D) Party and the Alliance of Liberals and Democrats in Europe (ALDE) voted against inviting him.
Mr Giegold’s Green Party is among those wanted Mr Juncker – who was yesterday reported to be willing to quit if Mr Selmayr is forced out – to be given a chance to attend.
The new job for Eurocrat Mr Selmayr, who is a close personal ally of Angela Merkel, comes despite being blamed for a series of high profile leaks about the Brexit process, raising questions of his suitability for the role.
As secretary-general, Mr Selmayr leads the EU civil service of 33,000 staff, with officials responsible for Brexit contingency planning reporting to him.
The appointment has raised eyebrows across Europe, with the governments of Hungary and the Netherlands among those voicing their concern.
MEPs said the hiring process for his job left the EU a laughing stock that would prove more damaging than the existence of Eurosceptic parties.
European Parliament Brexit co-ordinator Guy Verhofstadt insists the way the European Commission has handled the appointment of Martin Selmayr is “bad for Europe”.
The European Commission has previously insisted procedure was followed when hiring Mr Selmayr.
A Commission spokesman said: “There was and is a common understanding between the Commission and the European Parliament that the Commission has four days to submit the replies. We have received the questions . Thus, the answers will be provided in the course of today.”