Arbitrator mandate ends: replacement and repeating the hearing

When an arbitrator leaves office early, the tribunal must be reconstituted in an orderly way. Sections 590 and 591 ZPO connect termination of the mandate with appointment of a replacement arbitrator. The parties' agreement then determines whether the hearing already held can be used.

The key question is whether the hearing must be repeated in full. Section 591(2) ZPO generally permits the tribunal to use the procedural results already obtained. This includes the hearing record and the other files. A different agreement between the parties takes priority.

This article covers only departure from office, appointment of the replacement arbitrator and continuation of the hearing. A challenge based on bias is a separate issue with different requirements.

When the arbitrator mandate ends

Under section 590(1) ZPO, the mandate ends when the parties agree or when the arbitrator resigns. The parties may also agree on a procedure for ending the mandate. That procedure remains subject to the statutory framework in section 590(2) ZPO.

If the arbitrator cannot perform the duties or fails to perform them within a reasonable time, either party may apply to the court for a decision ending the mandate. This requires that the arbitrator does not resign, the parties cannot agree or the agreed procedure does not end the mandate. No appeal is available against that decision.

How the replacement arbitrator is appointed

Section 591(1) ZPO requires a replacement arbitrator when the mandate ends early. The replacement must be appointed under the rules that applied to the arbitrator being replaced. The arbitration agreement and incorporated procedural rules therefore come first.

The appointment of the replacement is separate from the reason why the first mandate ended. The new appointment should restore the agreed appointment mechanism. This may involve party appointment, appointment by a named body or another procedure set out in the clause.

When the hearing must be repeated

Section 591(2) ZPO allows the tribunal to continue with the procedural results already obtained unless the parties agreed otherwise. The provision expressly refers to the hearing record and the other files. Continuation is therefore generally available.

A full repetition may still be required if the parties agreed to it or if the new arbitrator cannot sufficiently assess the existing procedural basis. The review should cover recorded statements, unresolved evidentiary issues, arguments already discussed and the specific role played by the departing arbitrator in the hearing.

Which procedural results can be used

Use of the prior procedural results requires a reliable case file. The hearing record should show which statements were made, which evidence was taken and which requests remain open. Additional documents must be fully available to the new arbitrator.

The parties should therefore provide more than the last hearing note. The case file should contain the arbitration agreement, appointment documents, records, exhibits, procedural orders and correspondence about the departure. This makes it possible to assess whether continuation preserves the same basis for both parties.

Difference from a challenge and procedural delay

Departure under sections 590 and 591 ZPO concerns the end of a mandate and the replacement appointment. The article on early termination of the arbitrator mandate addresses the preceding question of resignation or a court application.

A challenge based on bias raises a different issue. The topic page on preparing arbitration helps organise the case file and procedural record. Court assistance under section 602 ZPO concerns evidence taking rather than replacement of an arbitrator.

Documents needed now

The first review should include the arbitration agreement, appointment rule, appointment of the departing arbitrator, resignation or decision ending the mandate and all notices sent to the parties.

For the question of repeating the hearing, add the records, exhibits, evidentiary requests, procedural orders and correspondence. A short chronology shows which procedural steps are complete and where the replacement arbitrator will enter the case.

What to record when the proceedings continue

When the replacement arbitrator joins the tribunal, the tribunal should clearly set out the next procedural steps for the parties. This includes the case file to be used, any additions, outstanding evidence issues and the next hearing. A clear procedural order prevents later uncertainty about the scope of the earlier hearing.

Objections to continuation or requests for repetition should be reasoned specifically. A change of person alone does not answer the procedural question. The key issue is which procedural basis will be adopted and which perception or evidence issue remains open.

Common questions on replacement appointments

Must a replacement arbitrator always be appointed?

Yes. Section 591(1) ZPO requires a replacement arbitrator when the mandate ends early. The original appointment rules apply to the replacement.

Must the entire hearing be repeated?

Not automatically. Section 591(2) ZPO permits the tribunal to use prior procedural results unless the parties agreed otherwise. The record and files must provide a reliable basis.

Who decides whether the existing record can be used?

The tribunal may continue using the prior procedural results. An agreement by the parties requiring a different approach must be respected.

Can a party apply to the court to end the mandate?

Yes. Under section 590(2) ZPO, either party may apply if the arbitrator cannot perform the duties or fails to do so within a reasonable time and the stated conditions are met.

Is departure the same as a challenge based on bias?

No. Sections 590 and 591 ZPO govern early termination, replacement and continuation of the hearing. A challenge based on bias must be reviewed separately.

Next step

Contract, arbitration clause, correspondence and deadlines should be collected. It can then be assessed whether negotiation, preservation or arbitration is central.