Belgium is considering extending its F-16 airstrikes against Islamic State jihadis in Iraq into Syria as part of stepped up efforts by the US-led anti-IS coalition, Foreign Minister Didier Reynders said Wednesday.

"I think you cannot just limit your actions to Iraq without pursuing these actions across the border when these terrorist groups cross the border" into Syria, Reynders told Bel-RTL radio.

"The Netherlands has come to the same conclusion and the Danes, and I think we are in the same position," he said.

Belgium launched its first attacks against Islamic State (IS) targets in Iraq in late 2014 but, like several other countries in the coalition, it decided against extending the air campaign into war-torn Syria amid public fears over getting dragged into a wider conflict.

However the bloody Paris attacks in November, which were claimed by IS, radically changed sentiment in favour of strikes in Syria.

As well as the Netherlands and Denmark, Britain has also changed tack and launched its first sorties against IS targets in Syria in December.

Reynders said that against this backdrop, the government would take the matter to parliament where many MPs want to go further, perhaps even to involve Libya where IS has made recent inroads.

He gave no timetable.

Washington has pushed its allies hard to step up the campaign against IS. The Belga news agency said US Defence Secretary Ashton Carter had written to his Belgian counterpart Steven Vandeput urging him to support airstrikes in Syria.