The central government's policies on Hong Kong and Macao will remain unchanged "beyond all doubt", a senior official said on Friday in response to concerns over the omission of some routine terms from the Government Work Report.

Delivering the report at the first session of the 13th National People's Congress on Monday, Premier Li Keqiang said the central government would continue to uphold the "one country, two systems" principle.

However, he did not use the routine terms "Hong Kong people governing Hong Kong", "Macao people governing Macao" or "high degree of autonomy" when speaking about the two special administrative regions.

On Friday, Zhang Xiaoming, director of the State Council's Hong Kong and Macao Affairs Office, said the central government would continue to implement the "one country, two systems" principle, as upholding it was listed as one of the fundamental policies formulated at the 19th National Congress of the Communist Party of China in October for developing socialism with Chinese characteristics for the new era.

Being listed as part of basic policy means upholding the principle is a "long-term task", Zhang said, adding that he hopes people will not misinterpret the situation.

"The principle already includes the connotation that Hong Kong people govern Hong Kong, Macao people govern Macao and both regions have a high degree of autonomy," he said.

Work related to the two SARs is conducted with the emphasis on fully and faithfully understanding and implementing the "one country, two systems" principle, he said.

The principle has achieved great success and won wide recognition at home and abroad, Zhang said.

"Why would the central government change the policy, given that it has been a success and widely supported by people in Hong Kong, Macao and the Chinese mainland?" he asked.

Zhang said he sees promising prospects in the development of the Guangdong-Hong Kong-Macao Greater Bay Area, a national-level issue that is receiving key attention from the central government.

He quoted President Xi Jinping, who spoke at a meeting of the Guangdong provincial delegation to the NPC on Friday: "Development of the bay area must be well handled."

Zhang said he is confident about the bay area project and expects the area to become a world-class innovation and technology hub.

He Lifeng, minister of the National Development and Reform Commission, the top economic planner, called the bay area project a "millennium plan" when speaking with journalists on Friday, and said it should be more efficient, orderly and effective in the next stage.

It is necessary to plan well, especially in terms of industrial development, transportation and ecological environment, he said.

Carrie Qiu contributed to this story.