Hostility between Congress and Interior Secretary James G. Watt mounted yesterday when a House subcommittee recommended handcuffing Watt's discretionary powers to accelerate oil and gas leasing on the outer continental shelf.

In a long-awaited and sharply worded report, the House Interior subcommittee on oversight and investigations charged that Watt's program will slow down the "expedited exploitation" of offshore resources and could lead to "massive losses to the Treasury."

Last year, Watt approved a plan to offer almost 1 billion offshore acres for potential oil and gas leasing over the next five years as a step toward American energy independence.

The plan set off a storm of protests in the Democratic House and in many coastal states affected by lease offerings.

The subcommittee, headed by Rep. Edward J. Markey (D-Mass), accused Watt of defending his program "by repeatedly questioning the patriotism of his critics." Such attacks, the subcommittee said, are "irresponsible" and, when made by a Cabinet officer, "outrageous."

The Markey subcommittee said the Watt rhetoric "preclude a reasoned debate on the issues" involved in weighing economic and environmental needs in a national offshore-leasing program.

The subcommittee also accused Watt of playing "brinkmanship" with coastal states and fostering "an atmosphere of confrontation" between the federal and state governments. The panel charged that Watt has been "obstinate and unyielding, and has seemed to encourage a fight with his critics."

The subcommittee called it "ironic" that the secretary's confrontational approach had forced many of his opponents into court, where "an avalanche of litigation" threatens major delays in a leasing program Watt is attempting to accelerate.

Markey's report also contended that the Watt plan "floods the marketplace with large offerings," reducing the number of bids on individual tracts and cutting the fair-market value of the leases.

The report recommended that Congress deal "quickly and comprehensively" with questions raised by the five-year plan, which the subcommittee said ignored the spirit of 1978 congressional amendments to the Outer Continental Shelf Lands Act.

The recommendations included:

* Reducing the interior secretary's discretionary authority under the act and giving Congress veto power over leasing plans (a device ruled unconstitutional by the Supreme Court last Thursday).

* Amending the act to give coastal states "meaningful participation" in leasing policies off their shores.

* Continuing congressional oversight, and legislation if oversight fails, to guarantee that the leases are awarded at fair market value.

* Returning to the narrower pre-Watt leasing policies, under which only high-potential areas were offered.

* Doug Baldwin, an aide to Watt, charged that Markey had refused a routine request to let the department review the report before releasing it, Associated Press reported.

[However, Baldwin said Watt's leasing plan was before Congress in 1981 for a statutory review period during which it could have been vetoed or amended. It was not altered at that time, and Baldwin said that amounted to tacit approval. However, some parts of the continental shelf have been put off limits to Watt since then through riders attached to appropriations bills.]