The Feyenoord defender has been starring for Louis van Gaal’s Oranje side in Brazil of late, impressing with his composed displays from right-back.
Even though he is a big player for his club side, Janmaat is expected to leave in the coming months after informing the Rotterdam outfit that he wants to move.
The Eredivisie giants will have little choice but to grant his wishes, with the 24-year-old now in the last year of his contract.
Scouts from United have been following the player for some time, and are thought to see him as a better option than current right-sided defender Rafael.
A move for Janmaat could follow swoops for Ander Herrera and Luke Shaw, who kicked of LVG’s summer spend for a combined £60m.
As well as the full-back, United are also keen on his Feyenoord team-mates Bruno Martins Indi and Stefan de Vrij.