*702By a demand dated June 21, 1983, respondent sought arbitration of its claim that petitioner had breached two agreements entered into on March 28, 1983. Each agreement contains a broad arbitration clause.
Although the record presents a substantial issue as to whether these agreements were in effect, petitioner initially participated in the arbitration proceeding and did not move to stay arbitration until on or about November 10,1983, over three months after service of respondent’s demand and several weeks after the arbitration commenced. Petitioner’s failure to move within 20 days of service of the demand and its participation in the arbitration bars this application (see, CPLR 7503 [c]; Matter of Lane [Abel-Bey], 50 NY2d 864; cf. Matter of Matarasso [Continental Cas. Co.], 56 NY2d 264). We note that the record is insufficient to enable this court to determine whether the arbitrator has exceeded the bounds of his jurisdiction. Under these circumstances, petitioner must await the final award of the arbitrator and, if it appears that the arbitrator has acted beyond his power, petitioner may seek to vacate the award pursuant to CPLR 7511. Lazer, J. P., Gibbons, O’Connor and Weinstein, JJ., concur.