Northern Ireland's latest electoral register currently contains some 82,000 fewer voters than last year.
The 7 per cent drop is reflected across all 18 constituencies but is most noticeable in key nationalist seats.
Gerry Adams's West Belfast constituency has lost more than 8,000 voters or 15.1 per cent.
Mark Durkan's Foyle constituency has lost nearly 6,500 voters or 9.3 per cent, while party colleague Alasdair McDonnell lost one in 10 electors in South Belfast.
However, chief electoral officer Douglas Bain said that applications to be included in the register are still arriving and that areas such as West Belfast were "traditionally slow" in registering.
The new register will be used for the scheduled Assembly election on March 7th next year.
Mr Bain said: "Right across Northern Ireland, all my offices have been receiving sackfuls of mail each day with registration forms and these people will be able to vote at the election."
Unionist-held constituencies also reflect the drop in registration. DUP MP Nigel Dodds's North Belfast constituency has lost some 5,300 voters while his party colleague in East Belfast, Peter Robinson, has just over 4,500 fewer electors.
Nationalists reacted to the drop with concern.
Sinn Féin's West Tyrone MP Pat Doherty said: "We warned that this would happen when other people, including the SDLP and unionists, were lobbying for the legislation - that it would lead to people losing their right to vote."
He added: "The precedent for the rollover of the electoral register has already been established when it was recognised that so many people were missing from the register for the last Westminster and local government elections that there was no other option but to use the previous register.
"Sinn Féin also believes people must be able to register up until much closer to the election. We believe that people should be able to register up until 11 days before the election."
His concerns were echoed by the SDLP chairwoman Patricia Lewsley. "The decline in registration seems steepest in the most disadvantaged areas. That means that it's those most in need who are losing out on their right to vote. That has to be a real concern in any democracy," she said.