One perk of getting old in Japan is a gift of a silver cup from the prime minister in the year you celebrate your 100th birthday. But from this year, new centenarians will be sipping sake from cheaper vessels.

The rising cost of supporting the aging population — almost 32,000 people were eligible to receive the gift this year, up 4.5 percent from last year — has prompted Prime Minister Shinzo Abe's government to present cups made of silver plate rather than sterling silver. The move halves the price to ¥3,812 per cup, public broadcaster NHK said, reducing total spending on the gifts by about 40 percent to ¥150 million.

The cost-cutting follows a move to make the cups smaller in 2009, and highlights the struggle the government faces to cap spending in a debt-ridden country where more than a quarter of Japan's 127 million people are older than 65. The proportion will rise to 40 percent by 2060, the government projects — a problem compounded by a faltering birthrate.