Americans can expect gasoline prices to level off, but prices won't drop despite the current glut of oil, Energy Secretary James Edwards said yesterday.

"I am not going to sit here this morning and tell you Americans can expect lower gasoline prices. But they can expect a leveling off," Edwards told the Senate Energy Committee while testifying in support of the administration's energy budget.

The former South Carolina governor, an oral surgeon, also said he had no idea when natural gas will be deregulated. He said a field study on the issue will take several months to complete. He refused to speculate when a decision will be made.

Democrats criticized him for stressing nuclear development while sharply reducing support for nearly all other forms of energy.

"I wish I wasn't a dentist. I wish I was a tooth fairy, and I could leave some of these projects under your pillows, but I can't do it," Edwards said.

Sen. Dale Bumpers (D-Ark.) criticized Edwards for slashing funds for energy conservation.

"We have a massive conservation program out there right now. It's price," Edwards said.

"That's cruel," snapped Bumpers.

"I agree with you that it's cruel," Edwards said. "But that's the way it is."

Edwards said the administration wants to increase all types of energy production, based on its hope to kick the economy into gear and lower the government's role. "What this country must have, and what the administration is committed to, is a more cost-effective and balanced approach to energy, coupled with a firm resolve to increase production of all types," he said.

Committee Chairman James McClure (R-Idaho), said he understands many lawmakers will have their own priorities and pet projects but that everyone should take his share of cuts.

Edwards defended federal funding of Tennessee's Clinch River fast breeder reactor on grounds the nuclear industry would not take it over now.

"The nuclear industry has had one blow after another. I doubt the nuclear industry would take it over now, they've been beaten down so badly by government regulation," Edwards said.

President Reagan has sent Congress a budget that includes $8.7 billion in energy programs for the coming fiscal year, including $500 million in spending increases for atomic power and oil stockpiling.

In other congressional testimony yesterday, Transportation Secretary Drew Lewis said "there is no litmus test" for which mass transit rail systems will survive or be scrapped by budget cuts