Angry Hong Kong investors, some banging gongs and others waving banners, scuffled outside a bank as frustration mounted over losses tied to investments linked to failed US bank Lehman Brothers.

Several hundred investors, many of them elderly retirees, marched to eight banks which had sold Lehman structured products, including ABN Amro, Standard Chartered, Bank of China, Citic Ka Wah and DBS Bank, demanding compensation for their losses.

Some investors tried to barge into a DBS Bank branch on Hong Kong island, jostling with security staff who linked arms to form a human barricade.

"The banks are cheating us," shouted some investors, while others banged gongs and waved protest banners accusing the banks of misleading investors on the risks involved. DBS said in a statement e-mailed to Reuters that a dedicated customer care centre had been set up to deal with concerns.

"DBS Bank (Hong Kong) Ltd is deeply concerned about the anxiety our customers are experiencing on this matter," a spokesperson said in the statement.

"Every customer is important to us and in cases where our standards are not met, DBS will not hesitate to make compensation," she said.

But one investor who burst into tears outside a Standard Chartered Bank branch said she wasn't convinced. "Basically, the banks are trying to stall us, they are not willing to have dialogue with us," said a lady surnamed Yim.

To deal with the stalemate, Hong Kong's Central Bank said it would make available mediation and arbitration services between investors and banks with the aim of "settling claims in a speedy, confidential and amicable way, or of narrowing the issues in dispute". But banks will have the right to refuse or accept mediation on a case-by-case basis. Local media reports say tens of thousands of Hong Kong investors had bought Lehman-issued and referenced credit-linked notes, called mini-bonds, worth HK$15.6 billion ($2 billion). DBS said earlier last week that most of the notes were worthless, provoking the investor backlash.