N.Y. Jud. Law § 5
A court shall not be opened, or transact any business on Sunday, nor shall a court transact any business on a Saturday in any case where such day is kept as a holy day by any party to the case, except to receive a verdict or discharge a jury and for the receipt by the criminal court of the city of New York or a court of special sessions of a plea of guilty and the pronouncement of sentence thereon in any case in which such court has jurisdiction. An adjournment of a court on Saturday, unless made after a cause has been committed to a jury, must be to some other day than Sunday. But this section does not prevent the exercise of the jurisdiction of a magistrate, where it is necessary to preserve the peace, or, in a criminal case, to arrest, commit or discharge a person charged with an offense, or the granting of an injunction order by a justice of the supreme court when in his judgment it is necessary to prevent irremediable injury or the service of a summons with or without a complaint if accompanied by an injunction order and an order of such justice permitting service on that day. Furthermore, no provision of this section shall be deemed to prohibit or prevent the conducting on Saturday and/or Sunday of any arbitration or mediation proceeding, provided all parties and the tribunal consent to such proceeding in writing. A writing purporting to provide consent of any party that is not prepared by the party shall only be sufficient to establish consent upon a finding by the tribunal by clear and convincing evidence, that such party has affirmatively consented to such proceedings on a Saturday or Sunday as the case may be; such finding to be made part of the record of any further proceedings.
N.Y. Jud. Law § 5