In an effort to head off potential terrorists, as well as drug and arms smugglers, U.S. Customs Commissioner William von Raab has issued emergency regulations to require increased security and background checks on employes with access to sensitive areas in international airports.

The regulations, which go into effect March 5 and will affect about U.S. 100 airports, will allow Customs to conduct background checks, including a review of criminal records, on anyone hired after Nov. 1, 1984, who works in areas including Customs inspection, baggage handling, ground crew operations, cargo terminals and outdoor airline ramps.

Any worker entering those areas -- including airline, airport or federal employes, as well as vendors -- will have to undergo a background check and display an identification badge issued by Customs.

In addition to the new regulations for employes, von Raab said yesterday that he has put into effect new procedures for handling incoming international flights when there is intelligence available indicating that terrorists might be aboard.

Customs inspectors across the country have been told that suspect flights should either be directed to an empty terminal or isolated on the airport tarmac and passengers removed in small groups.

The Reagan administration, through the Department of Transportation, has been drafting legislation that would take similar security precautions at all U.S. airports. But the legislation has not yet been introduced and would face a lengthy hearing and approval process.

Fred Farrar, a spokesman for the Federal Aviation Administration, said yesterday that airlines now check employment records for many employes, but not criminal records.

Von Raab said in an interview yesterday that he became concerned last year at the time of the hijacking of the cruise ship Achille Lauro that U.S. airports were vulnerable to foreign terrorists, especially on flights from countries where security is lax.

"It struck me that our Customs officers are particularly vulnerable -- since the first people a terrorist would see coming off the plane are the Customs inspectors," von Raab said.

"We don't want to inconvenience people, but we'd rather be safe than sorry," von Raab said, adding that he also hopes to find a way to refine the intelligence information Customs is receiving.

Detecting drug smuggling on incoming international flights has long been a Customs' priority. The Drug Enforcement Administration recently said it is seeking drug trafficking indictments against about 50 employes of a major commercial airline, which sources later identified as Eastern Air Lines.

Last August, Customs fined Eastern $1,377,600 after agents found 1,722 pounds of cocaine concealed in the air conditioning compartments on two Eastern flights to Miami from Colombia.

A year ago, Customs seized an Avianca Airlines Boeing 747 after 2,500 pounds of cocaine was found in a shipment of Valentine flowers from Colombia to Miami.