Noting that the expanded Election Committee will reflect broader representation of different sectors in society, Lam said she is confident that the committee will represent the city's overall interest and help the city to better integrate into the nation's overall development.

Sunday's balloting is the first since the nation's top legislature adopted a decision in March on improving the electoral system of the Hong Kong Special Administrative Region.

The Election Committee, expanded from 1,200 members to 1,500, is tasked with nominating candidates for chief executive and the 90-member Legislative Council, and electing the chief executive and 40 lawmakers.

For the contested 364 seats, about 5,000 registered voters of the contested subsectors will cast their ballots today.

After the polls end at 6 pm, all ballot boxes will be delivered to the central counting station at the Hong Kong Convention and Exhibition Center in Wan Chai. The public can enter the counting venue and see the counting process on a first-come, first-served basis.