The Washington Post--in its first move into cable television--yesterday announced plans to provide a mixture of local news, information and advertising on leased cable channels in the Washington metropolitan area.

The newspaper said broadcasting might begin as early as 1983 if leases are obtained on local cable systems.

In announcing the new project, Donald E. Graham, publisher of The Washington Post, said "Virtually all of the programming now being produced for cable systems is national in focus. We feel that in addition, the new 100-channel cable systems planned for this area will also want to offer their viewers more news and information about their communities.

"With the largest local news-gathering staff in this area, The Washington Post each day collects far more information about what is going on in the District of Columbia, Maryland and Virginia than any other news organization. These cable channels will give us another way to distribute this information to the community."

Thomas H. Ferguson, president of The Washington Post, said the company will begin immediate discussions with cable systems already operating in the Washington area and with all applicants for cable franchises that have not yet been awarded about leasing two channels on each cable system. No leases have been obtained, but Ferguson said the paper was "greatly encouraged by preliminary reaction" to the plan.

Just what will be produced on the local channels once the leases are obtained is unclear. Alice Rogoff, assistant to the publisher, said that the mix between video and text and the extent to which news and advertising are combined or broadcast on separate channels has not yet been determined.

"We're looking for a distribution system because we want to develop the product," she said.

"Basically most newspaper companies are interested in pursuing these kinds of ventures because no one is sure what the future holds," said newspaper industry analyst John Morton. "Daily newspapers have the data base. It would be foolish not to use that data base in a way that protects their business," he said.

The broadcast division of The Washington Post Co. operates four VHF television stations and operated Channel 9, which was then known as WTOP, in Washington until 1978. Lines between newspapers and cable broadcast operations are likely to be less clear than they may have been between daily newspapers and related television stations in the past, Morton said.

"This is going to be part of the newspaper. We're looking at a time in the future when some of the newspaper is not going to be delivered on newsprint," he said. Classified advertising and stock tables are likely to be among the first features for which a shift in delivery occurs, he said.

"It's obviously smart to be involved" in a venture such as the cable project announced by The Post yesterday, he said.