Some complained it was unfair to allow Chinese Americans to collect pensions from China. A netizen called Aodaliya wrote on Sina weibo: "China still has many uncovered by the urban pension system, who face big problems for their aging life. The country needs to address the aging problem domestically prior to overseas."

On the other hand, there are some supporters. Chang Kai, a labor expert with Renmin University, says the policy is mostly about fairness.

"The pension benefits depend on one's contribution payments made during their working life. It will continue to exist wherever you are. It's a kind of debt obligation the government has that will never change, even if one's citizenship changes," said Chang.

The heated responses reflect the crisis faced by China's pension system and the looming pension shortfall caused by China's aging population. The government has moved aggressively to expand pension coverage in recent years but for most residents that coverage is meager.

By February, the number of Chinese aged 65 and older had risen to 137 million, accounting for a record 10 percent of the population, according to China's National Bureau of Statistics. The number will rise to 331 million by 2050, while the number of those aged 15-64 will fall to 849 million, according to projections by the UN. The ratio of those aged 65 and over to those aged 15-64 will rise from 13 per cent in 2015 to 39 percent by 2050.

Yang Guihong from Beijing University of Technology said in some countries, like the UK, people can collect retirement welfare after obtaining local citizenship, which means some Chinese can get double pensions. "That is part of the rage of netizens in China," Yang said.

Guan Xinping of Nankai University notes this is a common practice throughout the world.

"Many countries, especially member states of the European Union, have signed agreements to ensure retirees who had worked in different countries receive their pensions through a single account," Guan told CRI.