It was confirmed last week England centre Mike Tindall had been fined 25,000 ($NZ51,000) and removed from the England Elite Player Squad following his well-publicised night out in Queenstown during the tournament.
Tindall - who has already indicated he would appeal the fine - is married to the Queen's granddaughter, Zara Phillips.
He was pictured in a compromising situation with another woman in a Queenstown bar on September 11, and later admitted misleading officials about the night out.
However, new Highlanders signing Haskell and England teammate Chris Ashton were also each given warnings and suspended fines of 5000 following their behaviour at the Southern Cross Hotel in Dunedin two days earlier.
Hotel maid Annabel Newton (23) had claimed the pair - together with a third player, Dylan Hartley, who has been cleared of any wrongdoing - had harassed her in a hotel bedroom on September 9.
Haskell is still in Japan, playing rugby for the Ricoh Black Rams in Tokyo, but Ms Newton told the New Zealand Herald she was leaving Dunedin after learning of Haskell's signing by the Highlanders.
However, Rugby Football Union professional rugby director Rob Andrew said in a statement the claims of "very serious wrong-doing" against all three players involved in the Dunedin incident were "entirely false".
"We do not believe the players had any intention to sexually harass or intimidate Ms Newton."
However, the incident was still "precisely the kind of dangerous, compromising situation" the players had been warned about prior to their departure for New Zealand, Andrew said.
Hartley had played no part in the "ill-considered exchange" with Ms Newton, but Haskell and Ashton's behaviour had still breached the England Elite Player Squad code of conduct, Andrew said.
The disciplinary action was a "strong reminder" of the standards required, with the suspended fines to be paid if the pair committed any further breaches prior to December 31 next year, Andrew said.
