Foreign bankers are fleeing Tokyo as Japan's nuclear crisis worsens, scrambling for commercial and charter flights out of the country and into other major cities in the region.

BNP Paribas , Standard Chartered and Morgan Stanley were among the banks whose staff have left since Friday's earthquake and tsunami, and now a nuclear plant disaster, according to industry sources with direct knowledge of the matter.

Expatriate staff at most foreign banks in Tokyo make up a small portion of the total, by some estimates less than 10 percent. But many are often in senior positions so their departure can have a significant impact.

And while Japan's investment banking market is famously tough, it's an essential place for large banks to be and can produce hefty fees.

The foreign banker presence on the ground in Tokyo now is very thin and depending on how long it takes them to return there could be lasting implications of that, said one banker. Every time there's a washout of foreigners in Japan they never quite return in the same numbers.

With bankers joining the growing exodus, private jet operators reported a surge in demand for evacuation flights which sent prices surging as much as a quarter. One jet operator said the cost of flying 14 people to Hong Kong from Tokyo was more than $160,000.

I got a request yesterday to fly 14 people from Tokyo to Hong Kong, 5 hour 5 minutes trip. They did not care about price, said Jackie Wu, COO of Hong Kong Jet, a newly established private jet subsidiary of China's HNA Group.

RADIATION FEARS

Radiation leaking from a crippled nuclear power plant spread panic across the country, emptying out Tokyo's normally bustling streets. Scores of flights to the city were halted and embassies warned citizens to leave or avoid the region.

The Tokyo-based International Bankers Association (IBA), which represents 16 major investment banks, issued a statement on Tuesday saying that none of them had closed business or ordered evacuations.

We are watching the situation as it unfolds, but right now, it's business as usual, Christopher Knight, Japan CEO for Standard Chartered, told Reuters on Wednesday, adding that his office was staffed and open.

Other banks, including Citigroup , J.P. Morgan and Morgan Stanley, also told Reuters that business was operating as usual.

While Japan markets remained open, and banks were indeed open, many financial professionals, particularly those from outside Japan, were doing everything they could to get out of the country.

IFR, a Thomson Reuters publication, spoke with 14 bankers from the bond syndicate and equities desks of Citigroup, J.P. Morgan, Deutsche Bank , Morgan Stanley, Bank of America-Merrill Lynch and BNP Paribas who had fled for the safety of Hong Kong, Singapore and Seoul through the week or were trying to get out.

Foreign bankers choosing to remain in Tokyo and Japanese bankers said that it was anything but business as usual at the moment with communications patchy, rolling blackouts, thinly-manned desks and so many people looking to leave.

It's been almost impossible to get hold of investors since the quake hit, said one syndicate banker at a U.S. house from the safety of Hong Kong.

While the banks were not officially relocating people, they were accommodating employees and their families who wanted to leave.

At the end of the day, it's the employees choice whether they flee or stay back, a banker at a European investment bank said. Asked who was taking up the option to leave, he said: Who isn't? Everyone is trying to get out. Wouldn't you?

SIMILAR TO SARS

Several bankers compared the situation to the outbreak of SARS in 2003. Severe Acute Respiratory Syndrome (SARS) emerged in southern China in 2002, swept through Guangdong province and Hong Kong before spreading globally in 2003. It infected some 8,000 people and killed around 800, which prompted hordes of foreign professionals to leave Hong Kong.

Morgan Stanley had moved its credit team out of Tokyo, a person with knowledge of the matter told IFR. Morgan Stanley's spokesman denied the bank had moved any staff out of Japan.

BNP Paribas has moved about 10 people away from Japan for business continuity purposes out of a staff of about 900, according to the bank's spokesman, Daniel Boyd.

A number of senior Standard Chartered staff left Japan on Saturday morning for Hong Kong and Singapore, a person with direct knowledge of the situation said.

We have contingency plans and if the situation changes this may involve moving some staff to other locations as needed to ensure business continuity, a Citi spokesman said.

A J.P. Morgan spokeswoman said no business, teams or desks had been relocated out of Japan.

The low foreign banker presence in Tokyo has also been exacerbated by many bankers on business trips abroad not returning to Tokyo. If you're a Japan banker that's just done a trip to Mumbai, you can bet they're calling their home base to see if they can stay a while longer, another banker told Reuters.

(Additional reporting by Jonathan Rogers; Stephen Aldred, Elzio Barreto, Kelvin Soh and Haruya Ida; Editing by Michael Flaherty and Lincoln Feast)