Campaigners on Wednesday urged customers to ensure their banks stop billions of dollars in finance for companies making cluster bombs, which are about to be outlawed in many countries.

The Cluster Munitions Coalition said the financial services industry has provided about 43 billion dollars (31.6 billion euros) in investments or services to big arms firms that produce the lethal munitions since May 2007 and must stop the flow.

The bombs or shells release hundreds of smaller bomblets, but are inaccurate and unreliable, maiming and killing scores of civilians including many children even after conflicts are over, according to the United Nations.

"This is about banning investments that make profits from human suffering," said Paul Vermeulen, head of charity Handicap International, one of the pressure and aid groups in the coalition.

An international convention on cluster munitions is due to enter into force on August 1 after 30 countries ratified the ban agreed in 2007.

One hundred and five countries have signed the convention, but not those where the known remaining producers are located -- South Korea, Singapore and the United States -- including US weapons giant Lockheed Martin.

Forty-four of the 146 banks involved in the loans, investments or services are based in countries that have signed up to the ban, according to a report for the coalition.

They include Britain, France, Germany, Japan and Spain.

"Clients can influence the behaviour of financial institutions, they can say 'no, not with my money'," Roos Boer of charity IKV Pax Christi, one of the report's authors, told journalists.

The coalition also called on countries banning the weapons to starve the remaining producers by blocking such financing.

Government pensions funds in Norway, Ireland, New Zealand and Sweden have opted out of such investments, as have 21 banks recently, especially in Europe, the coalition said.

Another 17 banks and financial services companies have made efforts to disinvest because of the growing stigma on the weapons, they added.

Top lenders since May 2007 included Bank of America, with 436 million dollars, Citigroup (321 million dollars), Goldman Sachs (250 million dollars), Credit Agricole's investment arm Calyon (155 million dollars) and Barclays (154 million dollars), according to the report.

Banks, including Deutsche Bank and HSBC, also provided hundreds of millions of dollars each in investment banking services to munitions' companies, it said.

The report was based on financial databases and public information, but the UN has listed other producers in recent years in countries such as Russia and Israel.