Officials told the United Nations it would closely monitor Tiangong 1's descent, but believed there was nothing to worry about.
But not everyone agrees.
Astrophysicist Jonathan McDowell said pieces weighing up to 100 kilograms could make it through the atmosphere and slam into Earth's surface.
He added changes in the atmosphere could result in the space junk slamming anywhere on the planet.
"You really can't steer these things," he told The Guardian. "Even a couple of days before it re-enters, we probably won't know better than six or seven hours, plus or minus, when it's going to come down.
"Not knowing when it's going to come down translates as not knowing where it's going to come down."
Uncontrolled crashes of spacecrafts are nothing new, with NASA's Skylab space crashing into Western Australia in 1979.
The Soviet Salyut 7 space station also plummeted Earth in 1991.
When controlled spacecrafts return to Earth, scientists guide them to the Oceanic Pole of Inaccessibility - a four kilometre deep area of the ocean located 5000 kilometres off the eastern coast of New Zealand.
Since 1971 more than 263 vessels have found a resting place in the "spacecraft cemetery".