Hong Kong woman breaks record for fastest ascent of Everest: official
"She left the base camp at 1:20 pm on Saturday and reached (the top at) 3:10 pm the next day," Shrestha told AFP.
But Tsang still needs to present her claim to officials from Guinness World Records to receive certification of her feat, he added.
The Nepal government certifies that climbers have reached the summit but does not issue certifications for records.
Tsang and her expedition organisers, who are now en route to Kathmandu, have yet to comment.
The fastest woman to conquer Everest had been Nepali Phunjo Jhangmu Lama when she completed the climb in 39 hours 6 minutes.
In 2017, Tsang became the first Hong Kong woman to reach the top. It was her third attempt at scaling the Himalayan peak.
Up to 350 people have summited the mountain so far this spring, the tourism department said, even as the country battles a spike in coronavirus cases.
But at least two teams have said they scrapped expedition plans after some team members tested positive at base camp.
Nepal's weather forecaster has warned of deteriorating conditions in the area after Cyclone Yaas slammed into eastern India on Wednesday.