Emails sent by Rab Wilson, one of founders of Accountability Scotland, followed an instruction from the Information Commissioner that the Scottish Parliamentary Corporate Body (SPCB) should do more to help him find the information he was seeking.
The SPCB insists the block happened because Holyrood's communication system treated his emails as "spam" along with 16 million others. But Mr Wilson is not convinced.
He has suggested his emails to a senior parliamentary official and the Presiding Officer Tricia Marwick were "being deliberately and knowingly blocked by party or parties unknown".
He says he had been told his emails had now been "unblocked" and that he was now "whitelisted", which he says suggested they had been blocked and that he and others had been blacklisted.
Mr Wilson, a former psychiatric nurse, is best known for his five-year battle to force NHS Ayrshire and Arran to reveal hidden files on more than 50 adverse healthcare incidents, many of which had resulted in patients dying.
He wanted to know from the Scottish Parliament details on the number, fate and handling of petitions that had been submitted to the petitions committee since its inception.
However, the SPCB told him some of the detail he sought was not collated while the rest was in the public domain.
When Mr Wilson appealed to the Scottish Information Commissioner, Rosemary Agnew, she agreed with the SPCB on one point, but said the body had "generally failed" to comply with the Freedom of Information law in dealing with his request. That was on May 2. On May 6 Mr Wilson wrote to Ms Marwick seeking the information, claiming to have been "given the run-around for six months".
Mr Wilson emailed weekly for five weeks without response. However, on June 10 Claire Turnbull, head of information governance at the parliament, replied saying: "We have no record of having received correspondence from you addressed to the Presiding Officer."
Two weeks earlier Mr Wilson had received an email from the same official, not in reply to his but as a response to the Information Commissioner's ruling. She was seeking more detail from him. For example, when he had asked "How many of these petitions have been turned down?" Ms Turnbull said "It would be helpful if you could clarify what is meant by the phrase 'turned down' in the context of your request."
But he says he still received no satisfactory response to all his other emails. "I have sent dozens," he said. A day ago he replied to Ms Turnbull saying: "It is my belief that my emails were deliberately blocked as they relate to embarrassing failures by you and your department and your failure to answer four out of five Freedom of Information questions that were put to you about the performance of public petitions to the parliament."
But in an email this week, Ms Turnbull explained that the Scottish Parliament attracted a huge volume of email correspondence and therefore a robust security system was required. She said: "The Parliament receives approximately 20 million email messages a year of which approximately 16 million are identified as potential spam items each year."
She assured him action had now been taken to ensure his messages passed through Holyrood's filters.
A spokesman for the Scottish Information Commissioner said he could not comment at this time.