Former captain Zeeshan Ashraf and Adnan Maqsood have left for India and former captain Rehan Butt, Shakeel Abbasi and Waseem Ahmed have also joined the league.
The Federation has warned that the revolting players would face a life ban.
"Our stance is very clear any player who decides to go and play in this unauthorised league faces a life ban," PHF secretary, Asif Bajwa said.
"We cannot allow or encourage any player to take part in a league that is not recognised by the FIH no matter how much money is involved in it for the players," he said.
Pakistan, which has fared poorly in the ongoing Champions Trophy in New Zealand is already facing problems with finding quality players for the London Olympics due next year.
Bajwa admitted that the PHF was concerned about the status of some players who were presently members of the national team and playing in the Champions Trophy.
Shakeel Abbasi, Waseem Ahmed and goalkeeper, Salman Akbar are among those named to have signed contracts with the WHS.
"We know that initially when this series was being spoken off as an official event of the Indian federation some players had signed contracts with the organisers. But now the scenario is different and the players know this," Bajwa said.
The former Olympian said that the PHF was in touch with members of the Pakistan team to find out the factual position.
"Some players have informed the PHF that they entered into contracts in a different environment and situation but if the league was illegal they would not participate in it," he added.
"I don't blame the players specially Zeeshan Ashraf, Adnan or Rehan Butt for deciding to go to India. But the PHF needs to ensure they don't lose current players," former Olympian, Samiullah said.
Zeeshan Ashraf before leaving for India said he had no choice but to go and play the league.
"What else can I do, I don't have a regular job, the PHF is not selecting me and they don't allow us to play in domestic hockey by imposing an age restriction on players representing different teams on the domestic circuit. The fact is I have to feed my family and the WHS is paying us very well," Ashraf said.
He made it clear he had no regrets over his decision. Adnan Maqsood also said before leaving he didn't see what the fuss was all about. "I signed the contract nine months back and I have not been selected for Pakistan for a while now so why shouldn't I go and play abroad."