The company's executives are currently working on sealing a deal which will likely see it snapped up for around £320 million by Host Europe Holdings, which is backed by private equity firm Cinven.
Glasgow based Iomart suggested restrictions surrounding that transaction were the reason for not allowing journalists in to the AGM.
However PIRC, Europe's largest independent corporate governance researcher, indicated it saw no reason for media not to be allowed in. A spokesman said: "PIRC believes annual meetings of publicly listed companies should be held in a transparent manner and there is no valid reason why media representatives should be excluded. This attempt at restriction is very rare."
PIRC had previously recommended its clients oppose Iomart's remuneration report and a special resolution allowing it to allot shares for cash.
Sarah Wilson, chief executive of proxy voting agency and corporate governance adviser Manifest, said: "Some shareholders or their proxies or representatives will be present in the room able to listen to management's presentation but not all.
"The media serves as an important information source for remote owners who cannot participate directly.
"While no new information may be disclosed, the sentiment of other owners is very valid in helping to understand the situation.
"The company's response to this very reasonable request is really at odds with good practice and very disappointing."
The Iomart AGM took place at 2.30pm yesterday at the company's registered office in the leafy surroundings of the West of Scotland Science Park.
Prior to the meeting Iomart had said: "Given the current restrictions on communication due to Iomart being considered by the Panel on Takeovers and Mergers to be within an Offer Period, Iomart confirms that access to this year's annual general meeting of shareholders will be restricted to registered shareholders only.
"In particular, the restrictions mean that no new material information can be disclosed."
It is understood there is nothing specifically in the Takeover Code meaning non-shareholders cannot attend an AGM however if anything material were to be said at the meeting it would need to be released to the stock exchange.
Iomart chief executive Angus MacSween along with finance director Richard Logan and operations director Sarah Haran, who together have an 18.5 per cent stake in the business, are currently working with Host Europe to bring a proposed 300 pence per share offer to fruition.