The global stimulus packages are likely to provide massive opportunities for fraud, according to a report from risk consultancy Kroll. According to the report, corruption could swipe about $500 billion out of the $5 trillion, equivalent to Japan's national output in just 18 months, being poured into saving economies.

The reasons are pretty obvious. Most of the spending will involve juicy, big budget capital projects. These are the traditional targets of corruption, and under the counter deals done with a wink and a nudge.

"Because corruption, by definition, happens in secret, it is impossible to determine in detail who gets what,'' the report says. "Each stage of a procurement contract, though, offers opportunities for different players to take a cut. Officials overseeing the deal, bidders jostling for position, agents, middlemen, and politicians can all stick their fingers into the pie."

What that means is that governments will need to make the processes as transparent as possible and make sure they're providing enough funds for the watchdogs. And officials overseeing these projects will need to be rewarded on the outcome, not just for handing out the contract.