The 18-year-old, who is eligible for as many as five countries, has seen his stock rise since netting twice in United's 2-1 victory over Sunderland on Saturday, prompting mass speculation over which nation the winger will opt to represent.
The Brussels-born starlet is also eligible for England, Turkey, Serbia and Albania, and Wilmots has revealed that his efforts to steal a march on international rivals have proven futile, with the starlet yet to decide over which country to declare for.
"Manchester United told me that Januzaj has not made a decision to play for a national team yet, not for any country," the 44-year-old coach told reporters.
"We gave a clear signal [that we want him to play for Belgium] and now it's up to him. I will respect his choice."