Commerce Secretary Malcolm Baldrige said yesterday the best way to increase exports of coal from overcrowded U.S. ports is to ease federal regulations, take the job of harbor improvement out of the hands of the Army Corps of Engineers and leave it to local port authorities.

Baldrige's approach, if adopted by a Cabinet-level task force and by President Reagan, would mean a dramatic, controversial break with a long history of federal support of port development.

Baldrige heads a Cabinet task force that is considering ways of increasing shipments of coal from U.S. ports, which have been badly backed up for many reasons, including inadequate loading and coal-blending facilities, environmental regulations and the need for dredging and other habor improvements.

The Corps of Engineers presently is committed to three major port development projects at Norfolk, Baltimore and at Mobile, Ala., involving hundreds of millions of dollars each.

But Baldrige suggested federal money isn't the essential ingredient. There is plenty of money available to develop coal export facilities, either from private investors in this country, or abroad, where the coal would be shipped, he said.

"The business is there; the financing is there," he said."I guarantee it."

Instead of drawing on federal funds, port authorities could increase users' fees on coal shippers to pay for development, he said.

Baldrige cautioned that these are his opinions and not necessarily those of the task force. He could not predict how Reagan will react to the taskforce suggestions nor spell out how much congressional legislation would be needed to carry out such a policy. The task force review should be completed in several weeks.