According to sociologist Jan Hertogen and based on an analysis of the last local election results - without the votes of the new Belgians the extreme right wing part Vlaams Belang would have won much more in Antwerp. In the districts were the number of immigrants increased greatly such as Antwerp and Borgerhout, Vlaam Belang recorded loses.
In the Antwerp district a growth of immigrants to 6.9% of the population was coupled with a loss of 1.2% for Vlaams Belang. In Bogerhout it's the most dramatic: a growth of 7.5% went together with a loss of 4.6% . Borgerhout is the only district where Vlaam Belang lost votes also by the "old Belgians" (ie, ethnic Belgians).
In other districts, such as Deurne, Hoboken and Merksem there are not enough immigrants to make a difference in the election results. According to Hertogen this explains why Vlaans Belang got above 40% in those districts.
Hertogen's conclusion: If immigrants would not have been allowed to vote, than Vlaams Belang would have achieved a growth of 4%-9% in all districts except Borgerhout.
Source: HLN (Dutch)