American daredevil Nik Wallenda has walked a tightrope across the crater of an active volcano in Nicaragua, taking half an hour to traverse the boiling lake of lava spewing toxic gases.

Masaya, 635 meters high and 20km from Managua, is one of only eight volcanoes in the world with an active lava lake.

Wallenda started his 550 metre walk across the crater known as "The Mouth of Hell" at 8:20 pm Wednesday and finished 31 minutes later, sweaty and cheerful. 

For the stunt, he wore goggles and a respirator for protection from the noxious gases.

Wallenda, who is the seventh generation of the famed Great Wallendas family of stunt daredevils and circus performers, said gusts of winds caused him to lose his balance a little while the gases affected his eyes despite the goggles.

Wallenda, who has previously walked a high wire across Niagara Falls and made a blindfolded crossing between two towers in Chicago, said it was the longest and most dangerous highwire walk of his life.

But unlike those stunts, he had a safety harness for the volcano crossing, which was broadcast for ABC's "Volcano Live!" special and a local TV channel.

The feat was captured by 17 cameras and four drones.

The show began with his wife, acrobat Erendira, performing pirouettes on a hoop suspended over the lava lake.

In 2016, American explorer Sam Cossman, wearing a special suit to withstand the extreme temperatures, descended to the depths of the crater.

In 1538, Friar Blas del Castillo also made a descent, believing the lava was gold.