Mr van Buitenen has gained a reputation as a whistle-blower
Dutch MEP Paul van Buitenen has published a confidential internal report on abuse of staff allowances described by a colleague as "dynamite".
The report highlights money paid for non-existent staff via a system of "service providers" or accountants.
He posted a short summary of the report on his website and could face a reprimand for breaching secrecy.
British Euro MP Chris Davies who leaked details of the document last month said he was delighted it was now public.
"Paul's here as a whistle-blower. They [senior parliament officials] will be angry about this but only because they will look stupid," he said.
Among the revelations made by the internal auditors are a large number of lay-off payments made to staff of MEPs who were not re-elected.
Ten were made to assistants even though they were working for another MEP.
And one member of staff is said to have accumulated part-time payments from 12 MEPs over a three-month period.
The auditors also refer to abuse of travel costs and expenses. In one case, the expenses amount to three times the staff member's salary.
Not everyone on the budgetary control committee is impressed with Mr van Buitenen's decision to go public with the report.
Fellow Dutch MEP Jan Mulder, who had originally been in favour of making the details public, said he would not have breached the secrecy order.
"If I've signed for it, then I would keep it confidential," he said.
British Labour MEP Eluned Morgan said she had written personally to Parliament President Hans-Gert Poettering, calling for the report to be made public.
"It's been handled very badly. This drip, drip, drip is not helpful. I think it should be published [in full], there's no question about that at all. This will have taken away any excuse."
A spokesman for Mr Poettering said if the rules on confidentiality had been broken, it would be up to the committee's chairman to make a complaint.
Mr van Buitenen is no stranger to censure at the hands of the EU's institutions.
He was formally reprimanded a few months ago after he publicised an account of a meeting held behind closed doors with the head of the EU's anti-fraud office, Olaf.
More famously, he was suspended in 1999 while working as an official at the European Commission after he passed allegations of fraud in the commission on to the parliament.