"The Islamic Republic of Iran supports decisions made by the (Iraqi) people's elected representatives," foreign ministry spokesman Bahram Ghasemi said.

"The Islamic Republic of Iran has always supported Iraq's democracy, territorial integrity and national sovereignty," he added.

Iran is a key power broker in neighbouring Iraq and many of the militias that played a central role in ousting the Islamic State group are known to be close to Tehran.

Iraq's national politics has been in paralysis since the May 12 national elections, but Saturday's appointments were expected to solidify new alliances and pave the way towards forming a government.

"We hope we soon witness the election of the president and prime minister to form a new Iraqi government," said Ghasemi.

Lawmakers appointed as speaker former Anbar governor Mohammed al-Halbusi, a Sunni politician backed by a pro-Iran bloc led by Hadi al-Ameri's Conquest Alliance -- a coalition of anti-jihadist veterans close to Tehran.

The post of first deputy speaker was given to Hassan Karim, put forward by populist Shiite cleric Moqtada Sadr whose list won the largest share of seats in the election.

Baghdad and Tehran, which fought a brutal war from 1980 to 1988, came closer after the fall of Saddam Hussein in 2003 and the rise of Iraq's Shiite majority on the political landscape.