President Reagan yesterday postponed for "an indefinite time" the expected request that Congress approve deregulation of natural gas prices over a three-year period.

After Reagan met with his Cabinet Council on Natural Resources, Energy Secretary James B. Edwards said the group had again unanimously recommended deregulation but that action was not taken because of the "timing" involved. Edwards would not be explicit, saying only that the president "may want to get his economic policy package out of the way" before sending his deregulation plan to Capitol Hill.

Some officials at the Department of Energy had been telling interested parties, including representatives of natural gas producers, that deregulation would be proposed yesterday. A spokesman for the Natural Gas Supply Association, a producers' group, said they were "disappointed and disturbed" by the delay, calling it "a grave mistake."

Under terms of the current Natural Gas Policy Act, the wellhead price of newly discovered natural gas will be deregulated after 1985. About half of the gas then being produced, however, would remain subject to controls indefinitely. Advocates say deregulation would encourage the search for more gas and conservation by gas users. Economists are uncertain how much average wellhead prices would rise, but most expect them to add billions of dollars to gas users' costs.