Challenge to arbitrator

An arbitrator has to disclose circumstances raising justifiable doubts as to his impartiality or independence. If circumstances exist which give rise to such doubt, a party may challenge an arbitrator. If the arbitrator does not resign, the matter can be taken to the High Court (section 10).

Challenge to jurisdiction

If an arbitrator's appointment is challenged (this includes a challenge about the existence or validity of the arbitration agreement), then the arbitrator determines the matter in the first instance. But the aggrieved party may "apply" to the High Court for a determination of such question.
In the meantime, the arbitral tribunal may continue the proceedings (section 11).