The IRNA state news agency did not give details of the charges, but quoted a lawyer who named the expert as Meimanat Hosseini Chavoshi.

TEHRAN - An Iranian fertility expert accused of working with foreign "espionage networks" to downplay the country's population crisis has been arrested, state news agency IRNA confirmed on Sunday.

It did not give details of the charges, but quoted a lawyer who named the expert as Meimanat Hosseini Chavoshi.

She is listed by the University of Melbourne as working at its School of Population and Global Health, published widely on Iran's once-lauded fertility and family-planning policies.

On Saturday, hardline newspaper _Kayhan _reported the arrest of several population "activists... who, under the cover of scientific activities, had infiltrated state bodies".

It said they manipulated statistics and handed sensitive information to Iran's enemies as part of efforts at "cultural and social invasion".

Iran was once considered an international success story in population control, bringing birth rates down from seven per woman in the 1980s to 1.66 in 2016, according to World Bank figures.

Then-health minister Alireza Marandi received the United Nations Population Award in 2000 for his family planning initiatives, which had to overcome entrenched taboos in an Islamic society.

Chavoshi has written extensively about these efforts, which she described as the "fastest fall in fertility ever recorded" in a 2009 book.

But lately there has been concern that Iran overshot its target, with the number of births falling well below the level needed to keep the population growing.

In 2012, supreme leader Ayatollah Ali Khamenei said it was a mistake to have continued the family planning policies of the 1990s, and called for new measures to double the population to 150 million.

The _Kayhan _report said Iran's enemies were using population experts to counter these efforts by downplaying the gravity of the situation.

"There is evidence these individuals are connected to Western espionage networks," Nasrollah Pejmanfar, a member of parliament's cultural commission, told the newspaper.