About 170,000 people in the North of Ireland, some 13% of the electorate, will not be able to vote in the Assembly election because they have been removed from the register, a report by the Electoral Commission shows.
Another estimated 36,000 people who are on the register will not be able to vote on the day because they do not have proper photographic identity documents.
It is understood that the Electoral Commission report will be published some time in December. But it is understood that registration is down in all 18 constituencies, particularly among working class people and young people.
It was claimed that the Act was introduced to combat alleged electoral malpractice -- but nationalists believe the move was directed at their community and its traditional aversion to British government bureaucracy.
Under the old system of household registration, one form was completed per home, by the head of the family usually, and this form included the name of every individual entitled to vote at that address. It is thought 10% of households did not return forms.
A Sinn Féin spokesman said the new system was politically motivated and had made it more difficult for people to register.
``We have put in a major effort at grass roots level. We are happier than we were, but the changes will affect parties across the board and some parties will be looking at the figures with a certain amount of panic.''
He said they had conducted research ward by ward in certain constituencies and found that areas of multiple deprivation, both Catholic and Protestant, had suffered most from under-registration.