Belgian defender Toby Alderweireld says there is no need to panic over the likely absence of captain Vincent Kompany and Thomas Vermaelen from the line-up for their opening World Cup game against Panama in Sochi on Monday.

"We will just have to do without them," he told a news conference at the team's hotel in the Russian capital on Friday.

Kompany and Vermaelen continued training on their own after arriving in Russia with injury concerns, which could still rule them out of the tournament.

"The guys we had playing in our last games did very well and so we have to have confidence in them," said Alderweireld.

"And I'm sure a player like (Dedryck) Boyata is going to do well. He plays at Celtic and has enough experience.

"Thomas and Vincent are doing all they can to try and get fit but mentally it is always tough for those who are injured. But if I see how they are working on getting back, then I think all will be good."

Sunday is the deadline for injury enforced changes to the squad and Alderweireld suggested that Belgium may have to forge on in Russia without their inspirational captain.

"Kompany is our leader. His enthusiasm and love for the fatherland has spread to all of us. I don't think that we could embark on this adventure without him, but (we) will be putting the squad first," Alderweireld said.

"But we are getting on with preparing for the next game and for the moment we have to do without them."

The 32-year-old Kompany came off during Belgium's friendly against Portugal on June 2 with an injured groin but was still named in the squad for Russia by coach Roberto Martinez.

Vermaelen, also 32, has been out since the middle of last month after suffering a hamstring tear in action for his club Barcelona.

"We won't really need strong defending against Panama per se. But if we don't get three points from the game then I think it will be a bit of mini-crisis," added Alderweireld in one of the more bolder expressions of confidence at the tournament.