NBA team owners passed stricter measures to force compliance with player tampering and salary cap rules on Friday after a wild off-season where several top stars changed clubs.

The tougher regulations provide for fines of up to 10 million U.S. dollars, voiding of contracts, forfeiting of NBA draft selections and suspensions of team executives who seek to attract players while they are under contract to another team.

"We need to ensure that we're creating a culture of compliance in this league and our teams want to know they're competing on a level playing field and frankly don't want to feel disadvantaged if they are adhering to our existing rules," NBA commissioner Adam Silver said.

"What we are really seeking again is a cultural change in the league, that all the partners in the league are essentially saying this is the kind of league we operate."

The issue came to a head after stars Kevin Durant and Kyrie Irving joined the Brooklyn Nets shortly after becoming free agents -- when the official negotiating period for free agents and clubs had barely begun.

Other deals that were eventually consummated came to light before talks were even supposed to start.

There was also concern about players talking with each other about possible moves, such as Kawhi Leonard wanting Paul George to join him on the Los Angeles Clippers while George had a contract with the Oklahoma City Thunder.

"The ultimate goal here is to ensure compliance and to ensure that there's that appropriate tension that exists at the team," Silver said. "So there is sort of a significant threat that if a team doesn't comply that there will be consequences."

Among the ways the league will toughen the tampering rules is a random audit of communications for five NBA teams, Silver saying he has the ability to confiscate people's communication devices should he desire under the new regulations.

"I'm not looking to take devices," Silver said. "We do have the power to take people's devices. That is not something certainly in the first instance we would be looking to do. I think we can create the appropriate culture without certainly on a random basis people feeling that's necessary. We have lots of other tools available to us."

Fines, Silver said, have proven ineffective at deterring violations.

"There's a general sense in this league that among the tools we have to ensure compliance, fining authority unto itself may be one of the least effective tools," Silver said.

"So within the power that already has been vested in the league, there is the ability to impact competition directly by suspending executives, taking away draft picks and voiding contracts."

While not vowing a foolproof system, Silver warned potential violators that, "We believe through these tools, we're dramatically going to increase the likelihood that we're going to catch you."

Some issues the league wants to examine, such as changing the dates for free agency, must be done in conjunction with the players union.

But moves such as George leaving the Thunder for the Clippers show how much influence star players can have on other players and by extension, their teams.

An individual player's ability to change the fortunes of a team "provides enormous leverage for that player," Silver said.