The Hong Kong Arbitration Ordinance (Cap. 609) provides a mechanism by which a party to arbitration proceedings can challenge an arbitrator’s impartiality.¹ In CNG v. G & Others [2025] HKCFI 3598, the court was asked to decide on such a challenge and, in doing so, revisited the applicable principles for the removal of an arbitrator based on doubts about their impartiality. 

Background

This case involves two adversarial parties in a protracted dispute spanning more than four years during which the Tribunal issued four partial awards and courts in multiple jurisdictions made various orders. For background details, please refer to our article on 12 March 2024.²

Following allegedly prejudicial conduct and remarks by the Presiding Arbitrator during a hearing on 24 and 25 June 2024, CNG filed a challenge against him under Article 12 of the Model Law on 10 July 2024. The HKIAC dismissed the challenge on 2 October 2024.³ Pursuant to Article 13(3) of the Model Law, CNG applied to the Hong Kong court to decide the matter. 

Takeaways

After considering all relevant circumstances, the Hong Kong court rejected CNG’s contention that there were justifiable doubts about the Presiding Arbitrator’s impartiality. Key takeaways from the decision are as follows.

• Legal test for challenging an arbitrator: Under Article 12(2) of the Model Law, an arbitrator may be challenged only if circumstances exist that give rise to justifiable doubts about their impartiality or independence. The applicable test is the test for apparent bias – whether “an objective fair-minded and informed observer, having considered the relevant facts, would conclude that there was a real possibility that the tribunal was biased”. 
• Fair-minded and informed observer:This hypothetical observer is not a lawyer but possesses basic legal knowledge and understands the broader context. They assess the situation holistically and avoid jumping to conclusions based on isolated incidents. They are balanced, but not complacent or unduly sensitive or suspicious. In the arbitration context, such an observer may consider an arbitrator’s professional reputation and experience. An established reputation for integrity and wide experience in arbitration can make doubts about impartiality harder to justify.
• Timing of a challenge: Under Article 11.7 of the HKIAC Rules, a party must submit a challenge within 15 days of becoming aware of the circumstances giving rise to doubts about an arbitrator’s impartiality or independence. As CNG filed its challenge on 10 July 2024, the court held that it could not rely on events prior to 25 June 2024. CNG’s delay amounted to a waiver of rights to complain of facts and alleged defects and irregularities occurring before 25 June 2024. 
• Alleged sleepiness of the Presiding Arbitrator: CNG claimed that the Presiding Arbitrator was asleep intermittently for 10 to 15 minutes during the hearing on 25 June 2024. The court found no real risk of bias, noting: (a) the lengthy procedural history and hearing hours in this matter; (b) the timing of the alleged sleep episodes – during submissions on costs by the opposing party; and (c) CNG’s failure to raise an immediate objection. The court concluded that the fair-minded observer would not consider there was a real possibility of bias on the part of the Presiding Arbitrator. Further, CNG’s silence at the time indicated that they did not consider the sleeping episode had any material impact on the conduct of the hearing. 
• Alleged hostility towards CNG: CNG argued that the Presiding Arbitrator made a series of comments suggesting prejudgment and bias. However, after reviewing the hearing transcript, the court found that the remarks reflected preliminary views. Remarks can be robust and be expressed emphatically but be justified in light of the arbitration’s history. There is nothing improper in the Presiding Arbitrator commenting on the apparent merits of the case or the credibility of a proposition advanced to persuade the parties to focus on whether it would be cost-effective to pursue a line of argument or an aspect of the claim. A fair-minded observer would not conclude that the Presiding Arbitrator had predetermined the outcome regardless of the evidence. 

Comments

This decision sends a clear message: if a party intends to challenge an arbitrator, it must act promptly and within the timeframe prescribed by the applicable rules. The court was unsympathetic to delay and emphasised that the procedural deadline must be strictly observed. 

While challenges to an arbitrator’s impartiality are rare, this case illustrates that the result depends heavily on the specific facts. The threshold is high. Allegations must point to conduct that is clearly unprofessional or egregious. Momentary inattention or robust preliminary views expressed during a hearing are unlikely to meet that standard, especially where the arbitrator has a strong reputation for integrity and experience. 

Importantly, any concerns about an arbitrator’s conduct must be raised immediately. The court will not allow a party to stay silent and stand by until the contents of the final award are known and then attack the award on the ground that there has been a failure to observe the requirement of the appearance of impartial judgment. The reasoning behind this is that the Tribunal should be given the opportunity to deal with the alleged irregularity or defect, preserving the fairness and integrity of the arbitration proceedings.

1. See Articles 12 and 13 of the Model Law which have effect by virtue of sections 25 and 26 of the Arbitration Ordinance (Cap. 609).
2. https://hongkong.dentons.com/en/insights/articles/2024/march/12/challenges-to-arbitral-award-dismissed
3. Under Article 11.9 of the HKIAC Administered Arbitration Rules, HKIAC shall decide on the challenge unless the arbitrator being challenged resigns or the non-challenging party agrees to the challenge within 14 days from receiving the notice of challenge.