David Cameron is coming under pressure to use an open government summit in London over the coming days to announce action on so-called "phantom firms" which are used to launder money and siphon funds away from some of the world's poorest countries.
At the G8 summit in Northern Ireland earlier this year, the Prime Minister secured agreement from participants France, Germany, Italy, the US, Canada, Russia and Japan on a declaration that information on the real owners of companies should be available to tax collectors and law enforcers.
But campaigners want world leaders to go a step further and require registers of owners to be opened to the public, so that journalists, charities and other interested parties can use them to root out corruption.
A recent Global Financial Integrity report found that illicit financial flows from developing countries amounted to more than £550 billion in 2010, more than six times the total amount received in aid that year.
Much of the cash flowed through anonymous shell companies, which exist solely on paper and allow money to be shifted out of a developing country without law enforcement authorities being able to identify the individuals responsible.
The Africa Progress Panel found that the Democratic Republic of Congo lost more than £800 million between 2010 and 2012 - the equivalent of almost twice its combined health and education budgets - as a result of dodgy deals in the mining sector facilitated by phantom firms incorporated in the British Virgin Islands, along with other countries based in Bermuda, Jersey, Gibraltar and the UK.
Mr Cameron has said that he would personally like to see the whole world move to public registers of beneficial ownership of companies, and the UK is consulting on whether it can take this step unilaterally.
Anti-poverty campaign group One urged the PM to use the Open Government Partnership summit in London this week to commit the Government to a public register of who owns and controls companies, trusts and similar legal vehicles in the UK, as well as its Crown Dependencies and Overseas Territories.
Some 1,000 delegates from 60 countries around the world are expected in London over the coming days to discuss means of making governments more open, accountable, and responsive to citizens.
A spokesman for One said that the summit provided the UK Government with "the perfect opportunity to further establish its reputation as a true transparency champion by announcing its intention to implement a public register of beneficial ownership, helping to enable citizens in developed and developing countries to follow the money and hold governments and companies to account".
The UK should also work to ensure that the same level of ambition is reflected in an anti-money laundering directive being drawn up by the European Union, said the group.
"Preventing the abuse of anonymous shell companies and trusts can play an important role in stemming the huge volumes of illicit financial flows that rob Africa of the resources that are needed if the continent and its people are to make sustainable progress in the fight against poverty," said One.