A salvage team has rescued two of four South Korean crew members trapped on a cargo ship that capsized off the southern US state of Georgia, the US Coast has Guard said.

The Coast Guard said a third man was being removed after rescue teams drilled a hole near the stern of the ship to get to the trapped men. 

Nineteen members of the crew of the MV Golden Ray and an American harbour pilot were rescued on Sunday after the massive cargo ship, owned by South Korea's Hyundai Glovis, listed and caught fire.

However, four crew members remained trapped in the engine room of the vessel, which was lying on its side partially submerged in relatively shallow waters.

The Coast Guard said it had made contact with the four trapped crew members on Monday and a rescue effort was underway.

"Response crews will drill a hole to deliver supplies," the Coast Guard said in a statement on Twitter. "@USCG and salvage crews are developing an extraction plan to safely rescue the 4 #GoldenRay crew members.

"This is a slow, but safe process," the Coast Guard said.

The Coast Guard released video of a salvage crew standing on the enormous keel of the capsized vessel preparing to enter the ship.

The 656-foot-long (200-meter-long) Golden Ray was transporting vehicles when it became disabled in St. Simons Sound off the coast of Brunswick, Georgia, caught fire and turned over on its side.

The Coast Guard plucked crew members off the ship overnight using a hoist from an MH-65 helicopter.

According to the South Korean foreign ministry, 13 of the rescued crew members are from the Philippines, six are from South Korea and one is an American.

The MV Golden Ray is owned by Hyundai Glovis, the logistics arm of the South Korean automaker Hyundai, but flies the flag of the Marshall Islands.

The 71,000-ton vessel is capable of carrying around 7,000 vehicles and was built in 2017.