A photo shows people are queuing to register marriage in South China's Shenzhen City, Guangdong Province on December 31, 2015. [Photo: china.com]

In Shanghai, close to 3-thousand couples said "I do" at the city's marriage registration centers on December 31st.

This is around 9-times the usual figure.

Most of these couples say they've rushed to register their marriages so they don't miss out on the extended marriage leave entitlements.

"We wouldn't have come to register if there were no change to the marriage leave length."

"We don't want to miss out on the extended marriage leave."

The cut to the extended entitlement is part of the new amendments to the family planning law that came into effect on January 1st.

In China, all newlyweds are given three days' leave after tying the knot, but those aged above the "late marriage" ages, which were 25 for men and 23 for women, also used to get extra days that range from 7 to 20, depending on which city you live in.

As part of the previous family planning policies, the move was designed to encourage people to marry and raise children later in life, so as to ease population pressures.

But under the new rules, all couples, regardless of their age, only get 3-days off, which isn't sitting well with some couples.

"The marriage leave is too short under the new rules. We hardly have time for a honey moon."

"Getting married is a big issue that can't be wrapped up in just three days. I hope employers can consider that and give us an extension."

"There should be an interim period for people to adapt to the new policy."

Sociologist Yao Hua says the move by the government, while jarring for some, still makes sense.

"Considering the government has brought in new policies to encourage couples to have two children, this cut does make sense."

China's family planning policy was first introduced in the 1970s to rein in a surging population.

For decades, most urban couples were limited to one child and rural couples were allowed to have two children if the first child was a girl.

It's estimated the policy stopped some 400 million births.

However, its also been blamed for generating a number of social problems, including a decreasing labor force and an aging population.

To fix this, Chinese authorities began scaling back the restrictions in 2013, and announced earlier in the year that all couples across the country will now be allowed to have a second child.

The change is expected to add an additional 30 million more people to the labor force by 2050, while at the same time, drop the proportion of elderly people in China by around 2-percent.