The Department of the Environment has rejected charges that the new electronic voting machines could be open to tampering.
Following an examination of one of the machines, computer security company Zerflow claimed that the Powervote machines could not protect the "integrity" of ballots.
Electronic voting was used in seven constituencies during the Nice Treaty referendum, up from four in the May election. It will be used in all 42 constituencies in the next election.
"Voters can easily be duped into voting for the wrong candidates by simply taping a fake ballot to the front panel of the voting machine," according to Mr Tony Geraghty of Zerflow. Furthermore, the front covers of the machines were not secure, the company claimed.
"This could allow somebody to interfere with the ballot card and cause voters to select the wrong candidates. This action could very easily to go unnoticed and compromise the entire election in that constituency," said Zerflow in a report released to RTÉ under the Freedom of Information Act.
In addition, the keys needed to unlock the machine's console can easily be copied. "Zerflow was able to get a copy of the control console key made at a local shopping centre," it claimed.
In future, presiding officers should require a smart card and a personal identity number (PIN) to be able to turn on machines - though at the very least, the keys should be sent to polling stations separately from the machines.
Rejecting most of the criticisms, the Department of the Environment's franchise officer, Mr Peter Green, said nothing short of a full-scale conspiracy by polling staff would be needed for tampering to occur. The ballot paper used in voting machines could not be easily accessed: "The release button for the lower hinge is partially hidden. Zerflow personnel admitted that it took them sometime to find it," Mr Green said.
Keys for the machine would continue to be transported with the machine itself, though Mr Green said security seals would be used to guarantee that they had not been tampered with in any way.
He rejected Zerflow's suggestions that the rear cover of the machine could be interfered with, arguing that the machine stayed in the full view of polling station staff throughout polling days.
"It is not accepted that the voting is insecure. The version of the voting machine to be used in this country has more security features than the versions used in Holland and Germany where the issues raised by Zerflow have not occurred."
The supplier of the machines, Powervote, said electronic voting must be kept as simple as possible. "Adding complexity to a system often leads to operational difficulties and needlessly increases doubts," it said.
Large numbers of polling station staff and others located elsewhere would be needed in a successful fraud, said Powervote.
