The total marks the lowest number of newborns reported for any September since the agency started compiling related data on a monthly basis, the statistics office said.

In the first nine months of the year, the number of newborns fell 9.2 percent on-year to 252,000, official numbers showed.

During the third quarter of the year, the number of babies born in the country fell to 80,400, down 9,200, or 10.3 percent from a year earlier, marking the lowest three-month tally since 1981.

The number of childbirths per month has decreased on-year every month since December 2015.

Last year, the number of newborns dropped to a record low despite concerted efforts to tackle the problem.

The number of babies born in all of 2017 reached 357,771, down 11.9 percent, or 48,500, from a year earlier.

That figure was the lowest number of newborns tallied since the statistics agency started to compile such data in 1970.

The crude birthrate, which refers to the number of births per 1,000 people per year, also came to an all-time low of 7 last year, down from the previous year's 7.9. 

In addition, the total fertility rate, or the number of babies that a woman is projected to have during her lifetime, fell to 1.05 last year from 1.17, also marking a record low, the data from the statistical agency showed.

"It is highly likely that the total fertility rate for the country to be below 1," an agency official said. "This means that there are quite a lot of women who do not have a baby."

Coupled with a rapidly aging population, a low birthrate reduces the available workforce in the country and drives up welfare costs. Such a development can seriously undermine economic growth potential.

The South Korean government has poured 80 trillion won ($72 billion) into dealing with the low birthrate over the past decade, including measures to encourage people to have more children by offering various incentives, such as cash rewards.

Meanwhile, the number of deaths came to 22,900 in September, up 1.3 percent from a year earlier. (Yonhap)