BALTIMORE, NOV. 30 -- Dockworkers and waterfront management at the Port of Baltimore reached a tentative contract agreement today, averting a threatened strike.

Port officials said the pact contains significant changes that could help the ailing port regain lost business.

The Baltimore District Council of the International Longshoremen's Association was to vote today on whether to submit the proposed settlement to a ratification vote by members on Monday. The two sides agreed to extend the current contract, affecting about 2,000 dockworkers, until the vote.

"It's the basis for getting us into the 1990s," said Maurice Byan, president of the Steamship Trade Association of Baltimore Inc., representing waterfront management in the talks.

The proposed contract, to last for three years and 10 months, calls for new restrictions on a controversial and expensive job-security plan and adds a worker to the standard work crews. It also provides for flexible work scheduling, allows terminals to stay open longer, and for a midnight shift to load and unload ships arriving late at night. Those were items management considered vital to Baltimore's future.

Ship lines have been watching the talks closely, but no large-scale diversion of cargo has occurred.

ILA Local 953, the clerks' union and the only one of the port's five dockworker locals not bargaining as part of the district council, did not participate and had no agreement as of today. Talks were to resume today.