The policy, launched in the 1970s, has produced "very good results," said Wu Jianmin spokesman for the Chinese People's Political Consultative Conference, an advisory body to parliament.
There would be an estimated 400 million more people in China without it, Wu said.
"The one-child policy was the only choice we had given the conditions when we initiated the policy," Wu told reporters at a news conference the day before the CPPCC convened for its annual session. However, he added, "when designing a policy we need to take into consideration the reality."
"So as things develop, there might be some changes to the policy and relevant departments are considering this," Wu said without giving a timeline or details on which departments would be involved.
Wu's comments echo a position China's communist government has been thinking about for some time. On Thursday, a senior family planning official said changes were being considered but that family planning policies would not be scrapped altogether.
Under the current mandate, Beijing limits most urban couples to one child and rural couples to two to conserve scarce resources. Critics say the policy has led to forced abortions, sterilizations and a dangerously imbalanced sex ratio due to a traditional preference for male heirs that has prompted countless families to abort female fetuses.
There are also concerns about China's aging population, with those aged 60 or older expected to top 200 million by 2015 and 280 million by 2025, according to the government.
The CPPCC includes representatives of China's main business, religious and other noncommunist groups. The session will run through March 14.
Wu said the hot topics this session include macroeconomic controls, government restructuring, employment rates, consumer price stability, climate change, and reform of the financial, educational and health care systems.