Iran inaugurated a long-awaited new port at Chabahar in the southeast Sunday, which it is hoped will be a major new trade hub linking India and Africa with Central Asia.

The first three shipments of Indian wheat to Afghanistan were unloaded in the morning, according to the Iranian ports organisation.

"Through this port, goods will be delivered to neighbouring countries at cheaper prices and in a shorter time," President Hassan Rouhani said at the port, in a speech carried by the state broadcaster.

The project was first conceived in 2003 and has so far cost around $1 billion, with India providing $235 million of the financing as it seeks routes that bypass regional rival Pakistan.

The port has been under construction for a decade by Khatam al-Anbia, the giant conglomerate owned by the elite Revolutionary Guards.

It can accommodate giant ships up to a dry weight of 120,000 tonnes, with further stages of development due to expand the port over the next 14 years.

"Chabahar will soon become an important commercial hub for Iran," Transport Minister Abbas Akhoundi said at the ceremony.

Iran has a broader vision of linking the Indian Ocean port with a railway through Zahedan on the Pakistani border up to Mashhad in the northeast.

But the project, aimed at facilitating trade with Afghanistan and Central Asia, has been slow to get off the ground.

Rouhani also underlined the importance of Chabahar as Iran's only port outside the Gulf, and therefore outside an area that is often the locus of tensions with the US Navy and Iran's regional rivals.