Can closing the gender gap help an aging Asia?

Women harvesting rice in Sangeh, Bali, Indonesia
Tom Cockrem | Lonely Planet Images | Getty Images
Women harvesting rice in Sangeh, Bali, Indonesia

Asia's aging demographics are expected to dent the region's long-term growth prospects, but closing the gender gap could help offset the impact of an aging population, says one economist.

Asia's population is graying; the proportion of people over the age of 65 is currently around 14 percent, according to data from the CIA Factbook, double that of 2010. By 2050, that number will nearly double again, rising to 25 percent according to U.N. estimates.

(Read more: The aging in Asia face a new decade like no other)

"The region faces a sharp demographic turn that will weigh heavily on growth and puncture deep holes in many fiscal balance sheets if better preparations aren't taken," HSBC said in a report. "In the next ten years, demographic headwinds could shave 0.5 to 1.2 percentage points off economic growth in China, Hong Kong, Korea, Singapore, Taiwan and Vietnam. That's not inevitable, but, without corrective policies, quite likely."

HSBC expects China may be able to stave off some of the effects of a declining working population by pursuing urbanization, which can "replenish" cities' aging workers with new workers from rural areas.

But it adds, "this is only of temporary comfort: the acceleration in ageing of the Chinese society will at some point overwhelm the urbanization process, leaving growth vulnerable. Better think of a way to make everyone a lot more productive – fast."

(Read more: Aging to challenge South Korea's economic transformation)

There might be one way to increase productivity. While Asia's gender gap has narrowed over the past five years, the average gap in economic participation measured by the World Economic Forum's Global Gender Gap Report for 2013 remains significant, especially in Japan and South Korea, said Eugenia Fabon Victorino, an economist at ANZ, in a note.

"A large gender gap represents a significant under-utilization of available economic resources," she said.

In a scenario analysis, she examined what would happen if Asia were to pursue policies raising women's labor participation rates to match men's as well as the effects of equalizing earnings between men and women without changing participation.

(Read more: This Asian nation faces a growing crisis from aging)

"If the region pursues policies that would raise female labor participation rates, this would add 314 million employees to the labor force. India and Indonesia will likely benefit most if labor participation rates are equal," she said. "Assuming we keep estimated earnings at current levels, equalizing the participation rates would increase total female earnings equivalent to 31 percent of gross domestic product (GDP) in India and 27 percent in Indonesia."

(Read more: China will get old well before it gets rich)

But if women's participation were kept at current rates, with earnings equalized between the genders, women's earnings would rise to around 58 percent of the region's GDP, she estimated, noting that in Vietnam, this would increase women's potential earnings by the equivalent of 50.8 percent of GDP.

Victorino isn't alone. Shinzo Abe, prime minister of Japan, told the United Nations in September that the advancement of women in society is directly correlated with economic growth; in other forums, he noted analysts believed Japan's GDP could increase as much as 15 percent if the country's women were able to participate in the work force more fully.

By CNBC's Leslie Shaffer. Follow her on Twitter: @LeslieShaffer1