TOKYO: Two big challenges to achieving sustainable growth in Asia are demographics and productivity, the head of the International Monetary Fund said on Wednesday.

Japan, South Korea, and China will need to take steps to deal with their rapidly aging societies, IMF Managing Director Christine Lagarde said at a seminar in Tokyo.

Improving productivity is a problem that all Asian countries face, she said.

Lagarde also said there was more room for Japan to improve access to childcare, lower working hours, and promote equal pay for equal work.