Over the next three weeks up to 20,000 will be granted permanent residency. Those eligible to apply under the amnesty include people who have lived in Belgium for the past six years, or five years in the case of those with children of school age. But he also warned that Belgium was becoming a target for organised illegal immigration. The reintroduction of border checks is likely to cause delays to travellers entering Belgium by car. International trains will also be subject to checks.
Immigration controls are already in operation at Belgium's airports.
Border controls within the EU have been abolished by the countries known as the Schengen group - Belgium, Germany, France, Italy, Luxembourg, the Netherlands, Austria, Spain and Portugal. Many non EU-citizens require a visa to enter the Schengen area, but once there they can normally move freely to other countries without any additional border controls. However Schengen countries can invoke special circumstances to restore temporary controls. The BBC is not responsible for the content of external internet sites Links to other Europe stories are at the foot of the page.