The Us have the option of signing the 23-year-old MTK Hungaria central defender on a permanent basis next summer if the loan arrangement proves to be a success.
"We've worked through the various requirements to complete this move, and we're now delighted to confirm Bela as a U's player for the foreseeable future," said chief executive Marie Partner.
"It's not often that Colchester United manage to sign a current international and with that comes the added complications of red tape and regulations involved in a foreign player transfer."