Ten Hag has agreed on a deal in principle with Manchester United to become their next permanent manager at the end of the season.
Manchester United are still to work out an agreement with Ajax, but a €2m buy-out clause is expected to be met by the English giants.
The 52-year-old is expected to sign a four-year contract, but the Dutchman made Manchester United sweat over his decision as he wanted certain guarantees before agreeing to take charge of the club.
Van der Vaart indicated that it was a bit disrespectful of Ten Hag to make Manchester United wait and feels he had nothing to think about once a club of their stature offered him a contract.
He stressed that the Dutchman should have taken up the job even if Manchester United had rejected some of his demands.
Van der Vaart said on Dutch broadcaster Ziggo Sport: “Nice, isn’t it? I read the reports that he kept Manchester United waiting but that really won’t keep you waiting.
“With all due respect to Ten Hag, if you receive such an offer, you should not think about it but just go bananas.
“You have to remain a bit humble.
“He is a good coach and has done a great job at Ajax but you don’t make Manchester United or other big clubs wait.
“Whether you are allowed to take decisions on transfers should not interest you at all.
“He will have absolutely asked but if United had said no, then he still should have gone there on a bicycle.”
The Dutchman also insisted that Ten Hag not being a big name in England might work in his favour, but he needs to be ruthless with players who will not be prepared to adhere to his style.
“They have a great squad but they are just playing very badly.
“It is not always the coach’s fault.
“You can say Ten Hag is not a big name in England, but maybe that is an advantage.
“If you are not going to cooperate with his plan then you can just get out.”
No announcement is expected to be made by either club before Ajax’s Dutch Cup final on Sunday.
