A South African pilot is being hailed for successfully making an emergency landing after noticing a cobra coiled under his seat, local media report.

Rudolph Erasmus was flying four passengers from Cape Town to the northern town of Nelspruit on Monday morning but was forced to cut short the journey after he felt something cold on his body, he told Times Live news website.

"As I turned to my left and looked down, I saw the [Cape] cobra putting its head back underneath my seat," he is quoted as saying.

The bite of a Cape cobra can kill a man in 30 minutes.

South African civil aviation commissioner has hailed Mr Erasmus as a hero, news24 website reports.

"Great airmanship indeed which saved all lives on board," Poppy Khosa is quoted as saying.

The pilot said he was unsure if he should tell his passengers after spotting the snake during the flight. He said he didn't want to cause a panic.

“I just said, 'listen, there's a problem. The snake is inside the aircraft. I've got a feeling it's under my seat so we are going to have to get the plane on the ground as soon as possible,” he is quoted as saying.

He managed to make an emergency landing at Welkom.

Engineers who stripped the plane did not find the snake, Mr Erasmus said.

He hopes to fly out of the plane on Wednesday.