The former Leeds striker, speaking exclusively to Football Insider, urged the 51-year-old to “test himself” in the “best and toughest league in the world”.
According to the Mirror (October 30th), Newcastle face a challenge to convince Ajax boss Ten Hag to join the club because of their impending fight against relegation this season.
The report claims the Tyneside club are also willing to appoint Marc Overmars as director of football.
The former Arsenal winger works with Ten Hag at Eredivisie giants Ajax.
The Magpies’ search for a new manager continues almost two weeks on from sacking divisive coach Steve Bruce.
Whelan believes Ten Hag lacks “confidence and belief” in his ability after the revelation.
“It’s the manager’s job to turn a losing side into a winning side and change the mentality,” he told Football Insider.
“It displays your credentials as a manager.
“You can’t be sitting there at Ajax, who are one of two decent sides in Holland, and say that about Newcastle.
“Let’s see how good a manager you are. If he’s not confident or doesn’t believe in his own ability – Newcastle shouldn’t be going after him.
“You want a manager who can come in and say ‘yeah, I can turn this around’.
“That puts some faith into his skills as a manager and into the players.
“Why not try and test yourself in the best and toughest league in the world? That’s where you will find your true standing as a manager.”