Legislature chief Diosdado Cabello made the announcement on national television on Thursday night.
On Tuesday, after announcing the president's death, the government said Maduro would both be acting president and the presidential candidate of the governing party.
The opposition cried foul. Venezuela's constitution specifies that upon Chavez's death, Cabello should have become interim president and elections for a new president called within 30 days.
The government said on Tuesday that the election would be convoked in 30 days. It is not clear when they will be held.