The North's Electoral Commission has admitted that certain groups have been left without a vote by new registration requirements.
The new electoral register contains about 180,000 fewer names than the register compiled under the previous household system.
The legislation under which the register was compiled was brought in on the back of persistent claims that some Sinn Fein votes were fraudulently cast. The effect of the bureaucratic new registration process is that genuine names have been removed. from the register.
In terms of religious and political ideology, the wards which lost the most voters are overwhelmingly Catholic and nationalist.
The largest declines in registration rates occurred in working-class areas of Belfast. Rural and wealthy constituencies continue to have the highest rates of registration, while there is a clear correlation between deprivation and percentage decline on the register.
The Electoral Commission claimed the report had had a positive impact on ``perceptions'' of electoral fraud, and that confidence levels in the electoral process have increased as a result.
But the report admitted that individual voter registration had an adverse impact on disadvantaged, marginalised and hard to reach groups.
Young people and students, people with learning disabilities and other forms of disability and those living in areas of high social deprivation were less likely to be registered and encountered specific problems with the new registration process.
The research particularly showed it was disadvantaged groups who are less likely to have eligible identification, such as a driver's licence or a passport.
it was also admitted that the move to individual registration meant that disillusioned voters were less likely to be on the register as they were less motivated to make the effort to register.
The report had few ideas on how to recover the lost voters. For example, it suggested that the new registration forms could be made available for internet download with the appropriate software.
Sinn Fein MP for Mid-Ulster, Martin McGuinness, said yesterday that it was `very obvious to anyone involved in the recent election campaign that the current system is deeply flawed'.
Mr McGuinness said he intended to meet with the Electoral Commission to discuss the ``many problems'' which his party had encountered during the recent campaign.
``These problems, be they registration or ID, can be directly traced to the SDLP and unionist sponsored legislation under which the register was compiled and the election fought,'' he said.
``This legislation was designed to have the effect of removing voters in disadvantaged areas from the register and was designed to target the Sinn Fein electorate. This legislation needs to be amended.''