Press Association Sport understands the midlands club will be called to account by the Aviva Premiership's governing body for breaching the league's code of conduct agreed by the 12 clubs.
Wales' match against Australia fell outside the IRB release window, which all Premiership Rugby clubs agree to respect.
Saints could face a fine for allowing North to play in Wales' 30-26 defeat in Cardiff on November 30.
North is thought to have clauses written into his contract stating Northampton must release him for all Wales' internationals, even outside agreed IRB windows.
But that goes against Premiership Rugby regulations, hence this disciplinary hearing.
Premiership Rugby are expected to release a judgement on the case on Thursday.
Saints are the first team to contravene this Premiership Rugby policy, and can expect a fine if the disciplinary ruling confirms the breach.
North will have no involvement in the hearing and his conduct is not under scrutiny.
As part of an agreement between Premiership clubs, only England players are allowed to be released by teams to play for their national side outside of the IRB's international window.