Members of Congress said yesterday they will seek to block important facets of the complex new regulations on oil sales and prices that were announced by the Carter administration Thursday.

At a Senate Energy Committee hearing. Sens. John Melcher (D-Mont.) and Howard Metzenbaum (D-Ohio) denounced the administration's proposal to let U.S. refiners start exporting some domestic oil products. Both predicted that the Senate will pass an amendment being prepared by another Energy Committee member, John Durkin (D-N.H.) that would prohibit most exports.

Meanwhilee, Rep. Henson Moore (R-La.) said he would continue his battle to prohibit implementation of a separate regulatory proposal that would triple the subsidy paid to east coast importers and refiners buying residual fuel oil from foreign sources.

Because many members of both houses left for their home districts Thursday night, it was difficult yesterday to judge how much support there might be for the efforts to block the regulations. But it seemed likely the administration would face a tough fight on both points.

Energy Secretary James Schlesigner Thursday announced a series of regulatory changes aimed at two different oil supply problems.

On the West Coast, there is an oversupply problem because oil companies have had difficulty selling their stocks of heavy crude oil and residual fuel oil refined from it. That has created a potential shortage of gasoline, because western refiners have slowed all refining opration to avoid adding further to residual fuel oil reserves.

Schlesinger announced a series of subsidy adjustments designed to promote the sale of west coast oil in domestic markets, and also said the administration would permit exports, on a temporary basis, of residual fuel oil to Japan and other buyers.

The problem on the East Coast is a shortage of domestic oil, which has forced Eastern refiners and utilities to rely heavily on expensive imported fuel.

Schlesinger announced the increase in subsidies as a means to reduce fuel costs in the east. The subsidies would funded by increasing oil prices for consumers elsewhere.

The proposed increase in Eastern subsidies became known a month ago and prompted opposition from Congressman representing other regions.

A Senate committee passed an amendment to block the increase, but a House committee barely defeated a similar amendment. Moore, the Louisiana Republican, said yesterday he would take the issue to the House floor.

The proposal to permit exports from the West Coast, a significant change in administration policy, drew a rich chorus of criticism in the Senate.

"It's absurd to export when we have a supply crisis," Metzenbaum said. "It's crazy," Durkin agreed. "Unbelievably insensitive," Melcher added.

The three said they would add an amendment to the next convenient bill to prevent the exports.