WASHINGTON, Jan 21 (Reuters) - U.S. President Barack Obama may order a hold on a proposal issued in the final days of the Bush administration to expand offshore drilling in previously banned areas, an Interior Department official told Reuters on Wednesday.

Shortly after being sworn in on Tuesday, Obama ordered all federal agencies and departments to halt pending regulations until they can be reviewed by incoming staff.

An Interior official said the department is waiting for clarification from the White House on whether a proposed draft of a five-year plan to lease areas in the Atlantic and Pacific waters for oil and natural gas drilling can go forward.

The preliminary plan would authorize 31 energy exploration lease sales between 2010 and 2015 for tracts along the east coast and off the coasts of Alaska and California.

Both presidential and congressional bans on drilling in most U.S. waters ended last year.

Separately, the Interior official said the department's plan to develop oil shale fields in the western United States may also be stopped by Obama's order.