DAVOS, Switzerland - Some of the world's biggest construction and natural-resources companies, their industries beset by corruption investigations around the globe, are starting to coalesce around a plan to clean house themselves.

Chief executives of Newmont Mining Corp. of Denver, Rio Tinto PLC of London and Bechtel Group Inc. of San Francisco, global leaders of their industries, are signing onto a "zero tolerance" pact against paying bribes being sponsored by a coalition of groups working with the World Economic Forum, according to company executives and forum organizers.Altogether 47 large multinational companies committed to the pact as of last night, representing at least $300 billion in annual revenue. "The momentum is building," said Fluor Corp. Chief Executive Alan Boeckmann, an organizer of the project.

The world's five largest oil companies -- many of whose top executives are here - also are being pressed to sign before the agreement's planned announcement tomorrow, but none have yet agreed. Officials of Royal Dutch/Shell Group and Total SA said they were considering the idea but already had their own zero-tolerance policies. A spokesman for London-based BP PLC said the company had declined to sign for that reason. Donald Campbell, a ChevronTexaco spokesman, noted that

Many big multinational companies already claim to observe strict prohibitions against bribery and influence peddling, and many have signed other pacts opposing corruption, so the latest effort is bound to raise questions about its effectiveness. This is the first such pact organized by the businesses themselves.

In addition, Newmont has been the subject of a criminal investigation in Peru for possible bribery and an environmental case in Indonesia involving influence-peddling allegations. Even the World Economic Forum hasn't been immune to problems. In October of last year, the group's chief executive and longtime director resigned after a feud over his ties to French telecommunications giant Alcatel SA. He says he didn't break the law and hasn't been charged.

Anticorruption watchdog Transparency International of Berlin, which monitors and ranks countries' corruption, and the Basel Institute of Governance back the agreement as a useful first move, though they cautioned it had to be followed up with enforceable action. "It is step one of an implementation program which is meaningful," under which firms would then commit to monitoring and disclosing results, said Jermyn Brooks of Transparency International.

Signers say joining the agreement has public-relations benefits but also steps up their public responsibility by inviting accountability. "It can work against you just as quickly, if you're not committed to it and practice what you preach," said Mr. Boeckmann of construction giant Fluor.

"Any time you take on a voluntary effort like this, you open yourself up to push back by people who may not believe you are living up to it," said Newmont CEO Wayne Murdy. He said the company would be exonerated in current investigations.

Under what the organizers are calling the Partnering Against Corruption Initiative, firms agree to a set of principles designed "to prohibit bribery in any form." The principles call for firms to set up extensive internal programs to educate and oversee company officials and business partners and also prohibit political contributions and charitable gifts designed to curry favor.

But the organizers' main aim is to get all the big players in key industries to sign the deal so that they can work in unison, with all feeling they are on a level playing field, and monitor each other. Organizers are concentrating on the construction, energy, and metals and mining industries because they frequently operate in the developing world and have some of the biggest corruption problems. In addition, they are each dominated by a handful of global giants, so it is relatively easy to get most of the industry leaders into one room where they can work things out face to face.

The project was initiated two years ago by corporate leaders like Mr. Boeckmann working with Transparency, the World Economic Forum and the Basel Institute. By last year, the pact had about 20 signatory companies, said WEF organizer Christoth Frei. Signatories to date have average revenue of about $10 billion, Mr. Frei estimated. Another dozen companies could sign on by tomorrow, he said. University of Basel Prof. Mark Pieth, founder of the Basel Institute, said enforcement of the pact for now will rely on "peer pressure." He and other organizers said their next step is to get executives who have signed the pact to come up with an enforcement structure.Japan's biggest construction companies.

One possibility, Mr. Boeckmann said, is a certification process by an independent monitor. Organizers are also seeking to sign up the big armaments firms, another huge global industry dominated by a few big players and long plagued by corruption scandals. Other companies being targeted include oil-field-services giant Halliburton Co., ensnared in a French corruption inquiry, and some of

"We already have a zero-tolerance policy communicated in our Code of Business Conduct,'' a Halliburton spokeswoman said. "If we have a rogue employee [who] violate[s] the Code, we move quickly to terminate the company's relationship with them so that we could protect the shareholders and everyone else who has a stake in the company."

U.S. law bars U.S. companies from engaging in bribery. But he said the document being circulated in Davos is "the kind of thing that we would like to support." Tom Cirigliano, of Exxon Mobil, said signing the document would be "redundant," because the company already has a zero-tolerance policy against bribery and because bribery is against U.S. law. He said he didn't know whether the company will sign.