The Feyenoord coach says he interacts with the Netherlands boss on a regular basis and believes his players are improving as a result of their experiences with the national side
Their friendship became strained back in 2004 when the Feyenoord coach was in charge of Ajax and Van Gaal was the club's sporting director, but it now appears they have agreed to put the past behind them.
"He calls before every international game and asks about the fitness of my players," Koeman told De Telegraaf.
"I reply with my honest opinion. He indicates which players he wants to use. Based on that, our contact is good. The national coach takes the club coaches into account.
"An example - he calls me on Monday and tells me 'I want to call up three of your players'. I say 'okay' right away because in the back of my mind I know the Dutch team is important for my players.
"The young Feyenoord players improve by being in Oranje."
He then took the time to discuss Van Gaal's approach regarding the national side and said he was in full support of his decision to freshen up the squad.
"It makes sense Van Gaal chose a new path. After the European Championship he had to apply the axe. The Dutch team needed that," he added.
"We all know Van Gaal is not afraid to do that [make choices]. He has the guts. He makes deals with young players and allows them to really develop."