Cindy Sun and her fiance are reconsidering their honeymoon plans after hearing that a bonus would be abolished that provides extra leave for couples choosing to marry later than the norm.

Sun, 29, a civil servant in Nanjing, Jiangsu province, had planned to tie the knot in May this year. But now there's a new wrinkle.

"Although Jiangsu has yet to implement regulations under the amended Family Planning Law, we are still worried we won't get the 10 extra days off," said Sun.

The legal age for marriage in China is 22 for men and 20 for women. While all newlyweds are granted three days of holiday, the previous law gave men over the age of 25 and women over 23 additional leave as a bonus for marrying later.

Many Chinese couples are likely to lose the extra holiday after changes to the law took effect on Jan 1. Regional regulations often lag behind national changes.

The exact number of days given to those who marry later varies from province to province. In Shaanxi and Sichuan provinces it was seven days.

The extra leave was initiated to encourage couples to marry and raise children later to soften population growth. With China abolishing its one-child policy and encouraging couples to have two children to offset an aging population, the law was amended and the late marriage leave was eliminated.

On average, Chinese are choosing to marry at around 25 - late by conventional standards - and the old policy had naturally lost some of its incentive value. But some couples had been banking on it.

"The extra leave is quite important to us because the normal three-day holiday will only be enough for our wedding," Sun said.

Some couples acted quickly. The Chaoyang office of the Beijing Municipal Bureau of Civil Affairs reported a spike in marriage registrations on the last day of 2015 to around 300 from the usual 70. Similar spikes occurred in Shanghai and Guangzhou.

The anxiety over the end of the late-marriage leave reflects a need to review the country's statutory annual holidays, as people are very particular about their "precious" time off, an editorial in Beijing News said.

"Ending extra holidays for late marriage does not necessarily mean less leave," said Sun Wenjie, a lawyer with Ling Yun Law Firm. "It takes time for local authorities to issue policies under new or amended laws."

Legislators in Guangdong province were the first to pass new regional regulations on family planning, giving new mothers an extra 30 days for maternity leave, on top of the existing 98 days.