Beijing's plans to change Hong Kong's electoral system will protect the city's international role, a senior Chinese official said on Tuesday, as critics decry the move as an end of democratic hopes in the former British colony.

Deputy Commissioner of China's Ministry of Foreign Affairs in Hong Kong Song Ru'an told reporters the proposed changes were an internal matter for China and were needed to "close obvious loopholes and deficiencies" in the city's political system.

China's rubber-stamp parliament, the National People's Congress, is expected to approve on Thursday a resolution that will reduce democratic representation in Hong Kong institutions and vet any candidates for "patriotism."