Mountaineer Tim Mosedale, from Everest Expedition
, said he passed the sheer rock face near the summit on May 16 and all that remains of it are some blocks, "probably a few tonnes each," that pose a potential danger to climbers.
Named after Edmund Hillary, the first climber to conquer the mountain with Tenzing Norgay Sherpa, the "Hillary Step" is considered the final test of endurance for Everest climbers.
The large rocks were "on quite an incline," Mosedale said. "My suspicion is that if anyone was to try and clamber over that remaining rubble and debris that it would cause it to move."
"It would probably be quite unstable, and would cause significant hazard to anyone who was below the climber. So really I think it's an area to be avoided now," he said.
However, Gyanendra Shrestha from the Nepal Tourism Board and Ang Tshering Sherpa, the President of Nepal Mountaineering Association, disputed Mosedale's suggestion that the "Hillary Step" has disappeared.
"This is a false rumor," Ang Tshering Sherpa said. "After this news surfaced ... I checked with Sherpas, climbers, and officials at the Base Camp. Hillary Step is intact."
He said the rock face had been covered by "excessive snowfall ... so some people assumed it had collapsed."
Shrestha said the step had been completely covered by snow so it "made it easier for climbers."
This season, 375 climbers received permission to attempt an ascent of Everest, the largest number since the summit was first reached in 1953.
It has already claimed a number of lives this year, including three in the past weekend.
Since Friday, more than 200 people have successfully scaled Everest, taking the total number this season to around 250, Shrestha said.
Recent deaths on the mountain
The three climbers who died over the weekend have been named as American Roland Yearwood, Slovakian Vladamir Strba and an Australian named in local media as Francesco Enrico Marchetti.
Yearwood, the 50-year-old American climber, died near the mountain's summit Sunday morning.
"Sherpas associated with the American climber are expected to reach the Base Camp this afternoon," Murari Sharma, managing director of Everest Parivar Treks told CNN. "Only then we'll get more details of his death."
Slovakian climber Vladamir Strb died near the "Balcony," a small platform near the summit in the so-called "death zone," also on Sunday, according to the Nepal Tourism Department.
Officials at the Tibet Mountaineering Association told local media
the Australian climber passed away "at an altitude of 7,500 m (24,600 ft) on (the) Tibetan side when he was descending to lower camps after suffering from altitude sicknesses at around 8,000 m (26,247 ft)," officials said.
In addition, an Indian climber, Ravi Kumar, has been missing since Saturday. Kumar was on his way down the mountain after reaching the summit when he became separated from his Sherpa guides near the Balcony, Thupden Sherpa, general manager of Arun Treks and Expedition said.
Sherpas accompanying the 27-year old have reached Camp 4 and three other Sherpas have been sent from Camp 2 to look for the missing climber, he said.
"Helicopters cannot fly at that altitude. So, only on-foot search is possible."
As many as 90% of deaths on the mountain occur while descending, Shrestha from the Nepal Tourism Board told CNN.
"They need to manage their energy, (their) oxygen accordingly. It's not only about making it to the top.
"Equally important is how you save energy to make it back to the lower bases. Most people force themselves to the top, leaving them with no energy to come back. You can't force yourself on Everest."