WASHINGTON (AP) _ Congressional negotiators are considering changes in legislation overhauling that nation's telecommunications laws that would make it harder for local Bell companies to break into the long-distance business.

Although measures that passed the House and Senate allow the Bells to provide such service, critics say they should not be able to do so until they are subject to real competition in the local phone business.

Lawmakers working to produce a final telecommunications bill were supposed to meet Thursday to take up this issue and to adopt a final agreement that would outlaw transmission of smutty material to children on computer networks.

But lawmakers _ given the opportunity to start their weekend early after the House adjourned for the week on Thursday _ decided to postpone the telecommunications meeting until next week, aides said.

While the proposals under discussion work differently, they all aim to expand the scope of competition that a Bell company must face in the local phone business before it would be free to provide long-distance service.

Billions of dollars are at stake.

One proposal from Rep. Jack Fields, R-Texas, would keep a Bell company out of long-distance service until a local phone competitor provides a ``fungible choice of services'' available to a ``meaningful number of people'' in a state.

``This language is designed to tie us up in every state commission and every federal court, and we reject it,'' said BellSouth spokesman Bill McCloskey.

The long-distance industry doesn't like it either, saying it's not tough enough. A competitor could make local phone service available and have no customers, the industry says.

So the long-distance industry is recommending that a Bell company be permitted to provide long-distance service only if a ``competitively significant portion'' of total residential and business customers in a given area actually buy local phone service from a competitor.

Another long-distance industry recommendation: Keep the Bell company out of long-distance until local phone service from a competitor is available to 50 percent of the homes in a given area and is bought by at least 15 percent of those homes.

Meanwhile, 34 senators, nine of them Republicans, are pressing negotiators to add to a final bill a provision that would require Bell companies to obtain Justice Department approval as well as that of the Federal Communications Commission before being able to provide long-distance service.

Lobbyists and aides on both sides of the issue say it is impossible to tell how much support any of these proposals are gaining.

Under the House bill, as currently written, local Bell companies may enter the $70 billion long-distance business if a competitor using some of its plant and equipment _ its wires and switches _ provides service to some residential and business customers.

Both bills also require the Bells to comply with a check list to ensure competition and to obtain FCC approval, but the Senate bill, as currently written, requires the FCC to determine that a Bell's entry into the long-distance market serves the public interest. The House bill does not.

Long-distance companies, consumer groups and the Clinton administration don't like provisions in existing bills. They assert that Bell companies would be free to get into long-distance, while they would continue to have sufficient monopoly power in the local phone business to block would-be competitors.

The Bell companies deny this and say existing provisions provide the right balance of protecting competitors and consumers while providing for competition to long-distance companies.

Responding to the proposals to make the Bell companies' entry into long-distance more difficult, all seven Bell companies told negotiators in a letter on Thursday: ``Given how far we have come in the past year and the number of concessions we have accepted, we are unwilling to accept this latest suggested language. ...It is now time to pass telecommunications reform without further delay.''