Chinese banks have a colossal mess of bad debts to clean up for the second time in as many decades, but they are unlikely to call in the financial world's most efficient mop and broom.

Foreign investors that specialise in buying up distressed debt are queuing outside the industry's door, but bankers say China's reluctance to pay the price of a privately funded clean-up means that door probably won't open -- to the cost of Chinese tax-payers and, ultimately perhaps, the wider economy.

Some economists believe the current mess will need a bigger clean-up than was required after the late-1990s Asian financial crisis. From 1999 to 2007, about $323 billion ($351.5 billion) in bad loans were swept out of the banks, according to a PriceWaterhouseCoopers (PwC) review of media reports over the period, in what amounted to a taxpayer-funded bailout.

"Sometimes the door is open for foreigners to come up and make money, and sometimes it's closed," said one veteran debt specialist who has bought and sold Chinese debt for global investment banks. He declined to be named due to the sensitivity of discussing China's sovereign debt.

"Our belief right now is that the door is closed."