Belgium has moved to expel an Egyptian preacher at the country's biggest mosque because he posed a "national security" threat, officials said on Tuesday.

Immigration Minister Theo Francken revoked the residency permit of the imam of the Saudi-financed Grand Mosque, near the EU headquarters in Brussels.

Belgium has been hit by several attacks since 2016, including suicide bombings claimed by the Islamic State group that killed 32 people at Brussels airport and a metro station.

"Everybody knows there is a problem with the Grand Mosque in Brussels. I decided to withdraw the residency permit of the imam of this mosque," Francken told Bel-RTL.

"We have had very clear signals he is a man who is very radicalised, salafist, very conservative and dangerous for our society and national security," Francken added.

Francken did not identify the imam but his office told AFP his name is Abdelhadi Sewif, a man of Egyptian origin who has lived in Belgium for 13 years.

Belgian authorities first decided in March not to renew the imam's residence permit but he has appealed against the decision and judges will review his case on October 24, an official said.

After the deadly Brussels bombings in March last year, the mosque defended itself against charges that it was preaching a puritanical strain of Islam and was even a hotbed of extremism.

Source: AFP