Faced with a plummeting population, rising labour shortages and widespread emigration, Prime Minister Viktor Orban of Hungary has long taken an unconventional approach to increasing the size and productivity of Hungary’s work force.

He offered university scholarships only to those who promised to stay in Hungary. He gave citizenship to ethnic Hungarians living beyond the borders. And late last year, he increased the amount of overtime employers can demand of workers — to 400 hours a year.

Mr Orban announced one of his most ambitious plans yet: Any Hungarian woman with four or more children will no longer pay income tax.

“We are living in times when fewer and fewer children are being born throughout Europe. People in the West are responding to this with immigration,” Mr Orban said in a speech. “Hungarians see this in a different light. We do not need numbers, but Hungarian children.”

No country in the European Union has a fertility rate high enough to replenish its population without immigration — but Hungary, with about 1.5 children per woman, is among the most sluggish. It also is among the most reluctant to accept foreign workers to help plug the gaps.

Even in the Czech Republic and Poland, where anti-immigrant sentiment also runs high, governments are planning to admit, or have already admitted, workers from across Asia. But Mr.Orban, a far-right leader, has said he does not want the color of Hungarians to be “mixed with those of others.” He led European opposition to refugees during the 2015 migration crisis and has boxed himself into a rhetorical corner that now makes it difficult to change direction.