The tanker, named Sanchi, caught fire after hitting the Chinese-flagged ship CF Crystal at approximately 8pm on Saturday.
Around 30 Iranians and two Bangladeshi nationals working on the tanker are reportedly missing following the incident, which took place approximately 160 nautical miles (nmi) east of the Yangtze River Delta.
Each of the 21 people on-board CF Crystal were of Chinese nationality and have since been rescued.
China Transport Ministry said in a statement: “Sanchi is floating and burning as of now.
“There is an oil slick and we are pushing forward with rescue efforts.”
Sanchi was sailing with 136,000t of ultra-light crude oil on-board at the time of the collision, which is worth around £44m.
Iranian company National Iranian Tanker (NITC) owns the vessel, which is operated by South Korean company Hanwha Total on a rental basis.
Sanchi was scheduled to arrive in Daesan, South Korea, after departing from Iran’s Kharg Island.
Meanwhile, the Chinese vessel, which also sustained damage during the incident, was carrying grain from the US to China’s southeast Guangdong province.
A total of eight Chinese vessels were dispatched to the accident location in order to conduct search and rescue operations.
Three of the vessels are also expected to undertake a clean-up operation.
In addition, South Korea has sent a coastguard ship and a helicopter to the scene of the collision, while the US Navy sent an aircraft to help find the missing crew members, reported Reuters.