Iran is seeking $2.5 billion investment to modernise its oil tankers fleet following the lifting of sanctions against Tehran, the managing director of National Iranian Tanker Company (NITC) was quoted as saying Saturday by state news agency IRNA.

Iran emerged from years of economic isolation after crippling sanctions were lifted in January in return for Tehran complying with steps to curb its nuclear ambitions.

Reuters reported last month two Chinese firms were pushing for multi-billion-dollar deals with Iran to modernise its shipping fleet and build a high-speed railway.

"To expand Iran's oil tanker activities, $2.5 billion will be invested in it," said Ali Akbar Safaei, managing director of NITC.

NITC has around 70 tankers, but many of them are ageing and require valid insurance, testing, inspection and certification — known as ship classification — to be able to ply international waters again.

Safaei said NITC was the first Iranian company that managed to rent its ships to foreigners after the lifting of sanctions.