Some 38 percent of single working women have no plans to have children, according to a survey by the Federation of Korean Industries.
The poll was conducted among 500 working women and shows that those who were married had on average 1.8 children, but the unmarried ones planned for no more than 1.1.
In spite of a government effort to boost childbirth, most women still consider it too difficult to balance work and raising children.
Around 44 percent said the government's measures such as maternity leave and flexi-time for working moms are not guaranteed in their workplaces.
The biggest group said their bosses simply refuse to accommodate them, while others feared repercussions if they took advantage of their legally guaranteed rights.
Still others said their company opposes the measures, though some said they are too busy. That meant 32 percent of working mothers did not take leave to raise their children. That breaks down to 41 percent in companies with less than 300 workers as against just 13 percent in big businesses.
Even those who did take maternity leave only took four or five months.