Columbia University and the union representing its 1050 clerical and technical workers negotiated into the morning hours in an attempt to ward off today's strike.
Representatives of both sides declined to comment on progress except to say they hoped a strike would not occur.
The union, District 65 of the United Auto Workers, has been seeking a 10.5 percent raise in pay and health benefits for its members on the Morningside Heights campus. The university has offered a 4.5 percent package.
The workers, who earn an average annual salary of $15,000, also want salary "parity" with higher-paid Columbia maintenance workers.
As the original midnight settlement deadline passed, at least 300 professors led by the group Faculty for a Fair Contract had made arrangements to teach today's classes off-campus to avoid anticipated picket lines.