Hong Kong teen activist Joshua Wong's new political party plans to field candidates in an upcoming election, marking the next step in the pro-democracy movement's evolution in the southern Chinese city.

Wong and several other young activists who led pro-democracy protests that gripped Hong Kong for 79 days in late 2014 officially unveiled their new party, called Demosisto, on Sunday evening.

Wong is the group's secretary-general, although at 19 years old he is two years too young to run for a seat in citywide elections for the Legislative Council set for September.

Three other members of the group are considering contesting seats in the upcoming vote, which will pit pro-Beijing parties against pro-democracy groups.