Japan's leaders need to confront the reality of the rapidly thinning labor force and acknowledge that a more ethnically pluralistic society can help ward off the looming demographic crisis, a British expert on immigration policy says.

"I profoundly believe that (Japan) can't function as a society without migration," Phil Wood, who describes himself as an "urban therapist," said in a recent interview with The Japan Times in Tokyo.

While Europe over the years has adjusted its way of dealing with migrants, Japan has stubbornly clung to a restrictive immigration policy, Wood said, noting Japan's situation is acutely reminiscent of how European cities more than 30 years ago saw migrants only as "guest workers."