The Republican-controlled Senate, in a victory for Interior Secretary James G. Watt, voted 51 to 48 yesterday to reject a temporary ban on leasing of federally owned coal. It had been approved by the Democratic House.

The proposed ban, which would have lasted through the end of the fiscal year Sept. 30, was rejected despite arguments from several Democrats that coal rights are being leased at "giveaway" prices that amount to a "massive ripoff of our American taxpayers."

The vote followed intensive lobbying against the moratorium by the coal industry, utility companies and Interior Department representatives.

"This assumed almost monumental importance," said Carl Bagge, president of the National Coal Association, which dispatched 50 lobbyists to fight the leasing moratorium. "We're working for coal, God and America. All we want is to make a buck and develop coal resources and bring fuel to America."

Pressure for a leasing ban grew after a recent report from the General Accounting Office, Congress' investigative arm, that coal rights recently have been leased for $100 million below fair market value.

The House included a four-month leasing moratorium in its version of a supplemental appropriations bill for the rest of the fiscal year, but the provision was stricken by the Senate Appropriations Committee.

In pushing for its restoration, Sen. Dale Bumpers (D-Ark.) argued in Senate debate on the proposal last week that leasing is a "mini-scandal of sorts" and contended that the nation is already producing 100 million to 150 million more tons of coal than it can use, leading to a 31 percent unemployment rate among miners.

"We need to catch our breath, carefully examine this program and make Uncle Sam a prudent businessman instead of the fairy godmother for major coal companies," Sen. Max Baucus (D-Mont.) added.

Western coal-state Republicans disputed the GAO assessment, argued that continued coal production is vital and characterized the Democrats' move as an effort to embarrass Watt.

"Aye, there is the rub," Sen. Alan K. Simpson (R-Wyo.) said, "because the issue swirls not around the merits of the coal-leasing program but around the personality of the secretary of the interior."

As for arguments that there is no market for federal coal, Sen. Malcolm Wallop (R-Wyo.) argued that an earlier 11-year moratorium contributed to recent high coal prices and asserted, "We are not talking about an already glutted coal market, we are talking about a market a decade from now."

A four-month moratorium would affect only a 700-million-ton lease sale scheduled next month in the Fort Union region of Montana and North Dakota. That is a small fraction of the 15 billion tons targeted by Watt for possible sale by 1985.

Moratorium foes argued that more is at stake in light of House proposals for a longer ban tied to appointment of a commission to review coal-leasing practices. Washington-area senators were divided, with Sens. Paul S. Sarbanes (D-Md.) and John W. Warner (R-Va.) voting for and Charles McC. Mathias (R-Md.) and Paul S. Trible Jr. (R-Va.) voting against.

The House and Senate disagreement over coal leasing must be resolved in a conference over the supplemental appropriations bill after the measure is approved later this week by the Senate. Still pending is a pay raise for senators, which has assumed grave significance to some members since a Senate vote last week to limit senators' earnings from speeches to special-interest groups.