Tehran (Agence France-Presse) - Iran's most expensive movie, Muhammad, which chronicles the childhood of the Muslim prophet, opened nationwide on Thursday, winning praise from early audiences.

Directed by Majid Majidi, the 171-minute film cost around US$40 million (S$56 million) - around 20 times higher than any other Iran-produced film - and was partly funded by the State. It took more than seven years to make and complete the film.

Majidi says the aim of his work, the first part of a trilogy, is to reclaim the rightful image of Islam, which he said extremists have distorted.

"Unfortunately at this time the impression of Islam is of a radical, fanatical and violent religion, which is not what it's about," he said in Montreal, where Muhammad had its international premiere, hours after screening back home.

"The barbaric acts of terrorism conducted by terrorist groups under the guise of Islam are not related to Islam," he said, alluding to beheadings and destruction of cultural treasures by Islamic State militants in Syria and Iraq.

"Islam is a religion of peace, friendship and love, and I tried to show this in the film."

The movie, Majidi said, captures Saudi Arabia more than 1,400 years ago and it offers "much more than stereotypical trains of Arabs on camels riding across yellow sand dunes."

It takes cinemagoers from the miraculous birth of the future prophet up to his teenage years, and is packed with miracles. The crew of Muhammad is indicative of the film's ambition.

It includes three-time Oscar-winning Italian cinematographer Vittorio Storaro and the score was devised by India's Allah Rakha Rahman, a double Academy Award winner for the Danny Boyle-directed blockbuster Slumdog Millionaire.

An earlier film production on the prophet, Muhammad, Messenger of God, was made in 1976 by Syrian-American film-maker Moustapha Akkad. It was a huge success with Shiite Iranians.

While Iran has denounced cartoons of the prophet like those published by French satirical magazine Charlie Hebdo, Shiites are generally more relaxed than Sunnis about depiction of religious figures.

Many showings of Muhammad in Shiite-majority Iran have already sold out, but the film has triggered controversy in the Sunni world.

Cinemagoer Mahsa Rasoulzadeh, 40, who watched the film with her mother and teenage daughter at Kourosh Cinema in west Tehran, said: "It was very moving for us."

No announcement has yet been made on when the two other parts of the Muhammad trilogy, covering the rest of his life, will be produced.