Local authorities went to the site and co-ordinated an evacuation and a clean-up.
Speaking to the Bali Post, Ubud police chief Kompol Gusti Nyoman Sudarsana said strong winds and rain had recently occurred in the area.
The terrifying moment was captured on CCTV, showing tourists screaming and running as several trees fell.
A video clip on Instagram showed people walking along the path when moments later debris was everywhere and people were running for safety.
Ubud’s Monkey Forest, also known as the Sacred Monkey Forest Sanctuary, is a nature reserve and temple complex in the village of Padangtegal where tourists go to see monkeys up close and participate in conservation activities.
It’s also a place for research, particularly on the monkeys' social interaction and behaviour with the nature that surrounds them.
According to the sanctuary’s website, the 12.5ha forest dates back to the 14th century and has more than 1200 long-tailed macaque monkeys living in it.
Monkeys are seen by the Balinese as sacred animals, symbolising protection and mischief.
The Herald has reached out to Ubud Monkey Forest for comment.
Freak accidents at the popular holiday island have killed tourists before.
In 2017, a former professional Belgian football player was killed by lightning while surfing in Bali.
Denis Dasoul, 34, was hit by lightning during a surf lesson in Kuta.
The incident also instantly killed his surf instructor.