Chinese couples have delayed having children by an average 2.1 years, citing economic and housing conditions.

In big cities like Shanghai and Beijing, couples generally said they delayed pregnancy plans until their combined monthly income reached more than 8,000 yuan (US$1,172).

The figures come from a nationwide survey by Beijing-based Horizon Research Consultancy Group.

More than half of respondents said they would opt to have only one child despite being allowed another under the country's population policy.

The survey covered 3,262 people aged over 18 in eight cities - Shanghai, Beijing, Guangzhou, Wuhan, Harbin, Taiyuan, Xi'an and Kunming - and eight towns in Guangdong, Liaoning, Zhejiang, Shandong, Heilongjiang, Shanxi, Hubei and Sichuan provinces.

The error margin is 1.09 percent, according to the survey.

Up to 85 percent of respondents in rural areas put economic status as the top priority when it came decision time for a child.

Sixty-four percent of respondents in cities and 59 percent in towns said they would first have a home of their own before starting a family.

Fifty-six percent of respondents said they would have only one child despite being eligible for another.

In cities like Shanghai couples said they would not consider children unless dual monthly income reached 8,078 yuan.

In second-tier provincial capital cities, the average dual income level is 5,169 yuan. In towns, the average is 4,454 yuan.

Unmarried respondents, on average, expected to bear children at 27.4 years old, 2.1 years later than married people at 25.3.

Population experts blamed rising living costs for later-life births.

Tang Jun, secretary-general of the Social Policy Research Center with the Chinese Academy of Social Sciences, said the cost to give birth and bring up children had increased a lot compared with 30 years ago when most families had more than two children.

For example, giving birth to a child now costs, on average, 5,000 yuan compared with 500 yuan in the 1980s.