A mystery British benefactor has added 100,000 British pounds (16.5 million yen) to the reward money put forward for information leading to the return of missing hostess Lucie Blackman.

The man, who describes himself as "an international businessman with a heart and enough money," contacted The Japan Times to announce that he wanted "to top the fighting fund up."

Lucie, a 21-year-old former British Airways flight attendant from Sevenoaks in Kent, was working as a hostess in the Casablanca club in Tokyo's Roppongi entertainment district before she disappeared on July 1. She has not been seen since.

"I've got kids of my own, and I know what the Blackman family must be going through," the man said. "The money has been deposited with a lawyer -- this is not a hoax.

"This investigation has been dragging on too long already," he added. "We have to make something happen."

Tim Blackman, Lucie's father, said, "This fantastic offer of a substantial reward is going to increase the odds of us bringing Lucie back."

Blackman, who had already put up his own reward of 1.5 million yen, said: "We have got through a great deal of money in the last eight weeks in the search for Lucie, and now we've got some proper money. Let's see what this brings out."

Sophie Blackman is in Tokyo at present to continue the hunt for her sister.

"We are elated as a family that there are still people who have genuine offers of generosity and kindness, and we hope this offer from our mysterious businessman will bring my sister back," she said.