AMSTERDAM, Netherlands — Paul Hiltemann had noticed a darkening mood in the Netherlands. He runs an agency for people wanting to emigrate, and his client list had surged.

But he was taken aback in November when a Dutch filmmaker was shot and his throat slit on an Amsterdam street.

In the weeks that followed, Hiltemann was inundated by e-mail messages and telephone calls. "There was a big panic, a flood of people saying they wanted to leave the country," he said.

Leave the stable and prosperous corner of Europe? Leave a land with generous social benefits and ample salaries, a place of fine schools, museums, sports grounds and bicycle paths, all set in a lively democracy?

The answer, increasingly, is yes. This small nation is a magnet for immigrants, but statistics suggest there is a quickening flight of the white middle class. Dutch people pulling up roots said they felt a general pessimism about their small and crowded country and about the social tensions that had grown along with the waves of newcomers, most of them Muslims.

"The Dutch are living in a kind of pressure-cooker atmosphere," Hiltemann said.

Sense of bewilderment

There is more than the concern about the rising complications of absorbing newcomers, now one-tenth of the population. Many Dutch also seem bewildered that their country, run for decades on a cozy political consensus, seems so tense and prickly and bent on confrontation.

Those leaving have been mostly lured by English-speaking nations such as Australia, New Zealand and Canada, where they said they hope to feel less constricted.

In interviews, emigrants rarely cited a fear of militant Islam as the main reason for packing their bags. But the killing of the filmmaker Theo van Gogh, a fierce critic of fundamentalist Muslims, seems to have been a catalyst.

"Our Web site got 13,000 hits in the weeks after the van Gogh killing," said Frans Buysse, who runs an agency that handles paperwork for departing Dutch. "That's four times the normal rate."

Van Gogh's killing is the only one police have attributed to an Islamic militant, but since then they have reported finding death lists by local Islamic militants with the names of six prominent politicians. The effects reverberate. In a recent poll, 35 percent of the native Dutch questioned had negative views about Islam.

Seeking security, peace

There are no precise figures on the numbers leaving. But Canadian, Australian and New Zealand diplomats in Amsterdam said that while immigration papers were processed in their home capitals, embassy officials in Amsterdam had been swamped by inquiries in recent months. Many who settle abroad may not appear in migration statistics, such as the growing contingent of retirees who flocks to warmer places.

Official statistics show a trend. In 1999, nearly 30,000 native Dutch moved elsewhere, according to the Central Bureau of Statistics. For 2004, the provisional figure is close to 40,000.

"It's definitely been picking up in the past five years," said Cor Kooijmans, a demographer at the bureau.

Ruud Konings, an accountant, has just sold his comfortable home in the small town of Hilvarenbeek. In March, after a year's worth of paperwork, the family will leave for Australia. The couple said the main reason was their fear for the welfare and security of their two teenage children.

Kids not safe cycling home

"When I grew up, this place was spontaneous and free, but my kids cannot safely cycle home at night," said Konings, 49. "My son just had his fifth bicycle stolen." At school, his children and their friends feel uneasy, he added. "They're afraid of being roughed up by the gangs of foreign kids."

Sandy Sangen has applied to move to Norway with her husband and two school-age children. They want to buy a farm in what she calls "a safer, more peaceful place."

Like the Sangens and Koningses, others who are moving speak of their yearning for the open spaces, clean air and easygoing civility they feel they have lost. Complaints include overcrowding, endless traffic jams and overregulation. Some cite a rise in anti-social behavior and a worrying new toughness and aggression in political debates and on the streets.

Until the killing of Pim Fortuyn, a populist anti-immigration politician, in 2002 and the more recent slaying of a teacher by a student, this generation of Dutch people could not conceive of such violence in their peaceful country.

After van Gogh's killing, angry demonstrations and fire-bombings of mosques and Muslim schools took place. In revenge, some Christian schools and community centers were attacked. Konings said he and many friends sensed more confrontation to come, perhaps more violence.

"I'm a great optimist, but we're now caught in a downward spiral, economically and socially," he said. "We feel we can give our children a better start somewhere else."

Space is at a premium in Europe's most densely populated nation, where 16.3 million people live in an area roughly the size of Maryland. Denmark, which is slightly larger, has 5.5 million people. Dutch demographers said their country has undergone one of Europe's fastest and most far-reaching demographic shifts.

Blaming immigrants for many ills has become commonplace. Conservative Moroccans and Turks from rural areas are accused of disdaining the liberal Dutch ways and of making little effort to adapt. Immigrant youths make up half the prison population. More than 40 percent of immigrants receive some form of government assistance, a source of resentment among native Dutch.

Immigrants said, though, that they are widely discriminated against.

Konings said the Dutch brought on some of the social frictions. The Dutch "thought that we had to adapt to the immigrants and that we had to give them handouts," she said. "We've been too lenient; now it's difficult to turn the tide."

To Hiltemann, the emigration consultant, what is remarkable is the type of Dutch people leaving. "They are successful people, I mean, urban professionals, managers, physiotherapists, computer specialists," he said. Five years ago, he said, most of his clients were farmers looking for more land.

Buysse, who employs a staff of eight to process visas, concurred. He said farmers continued emigrating as Europe cut agricultural subsidies. "What is new," he said, "is that Dutch people who are rich or at least very comfortable are now wanting to leave the country."