Former presidents, prime ministers, eminent economists and leading members of the business community will unite behind a call for a shift in global drug policy. The Global Commission on Drug Policy will host a press conference at the Waldorf Astoria hotel in New York to launch a report that describes the drug war as a failure and calls for a "paradigm shift" in approaching the issue.

Those backing the call include Ernesto Zedillo, former president of Mexico; George Papandreou, former prime minister of Greece; César Gaviria, former president of Colombia; Kofi Annan, former UN secretary general; Fernando Henrique Cardoso, former president of Brazil; George Shultz, former US secretary of state; Javier Solana, former EU high representative; Virgin tycoon Richard Branson; and Paul Volcker, former chairman of the US Federal Reserve.

The commission will call for drug policy to move from being focused on criminal justice towards a public health approach. The global advocacy organisation Avaaz, which has nine million members, will present a petition in support of the commission's recommendations to UN secretary general Ban Ki-moon.

The commission is the most distinguished group to call for such far-reaching changes in the way society deals with illicit drugs. Danny Kushlick, head of external affairs at Transform, the drug policy foundation that has consultative status with the UN, said current events, such as the cartel-related violence in Mexico, President Barack Obama's comments that it was "perfectly legitimate" to question whether the war on drugs was working, and the wider global economic crisis, had given calls for a comprehensive overhaul of the world's drugs policy a fresh impetus.

Kushlick described this week's conference as hugely significant. "What we have here is the greatest collection thus far of ex-presidents and prime ministers calling very clearly for decriminalisation and experiments with legal regulation," he said. "It will be a watershed moment."

Transform believes the case for overhauling the prohibition approach to drugs is now overwhelming. It quotes Nicholas Green, chairman of the Bar Council, who observed that drug-related crime costs the UK economy around £13bn a year. "Decriminalising personal use can have positive consequences; it can free up huge amounts of police resources, reduce crime and recidivism and improve public health," he said.

But while politicians no longer in office are vocal in calling for a change, incumbents appear less likely to back the idea of any radical shift in policy. In its 2002 review of UK drug policy, the parliamentary home affairs select committee, which included the prime minister, David Cameron, called for the government to "initiate a discussion" into the possibility of legalising and regulating drugs.

Despite the calls successive ministers have declined to endorse them.