A Chinese rocket has fallen back to Earth, but NASA says it would have been nice to know where it would end up. 

US Space Command said the Chinese Long March 5B rocket re-entered Earth's atmosphere over the Indian Ocean at approximately 12:45pm EDT on Saturday (2:45am AEST), but referred questions about “re-entry's technical aspects, such as potential debris dispersal impact location” to China.

“All space-faring nations should follow established best practices and do their part to share this type of information in advance to allow reliable predictions of potential debris impact risk,” NASA administrator Bill Nelson said.

“Doing so is critical to the responsible use of space and to ensure the safety of people here on Earth.”

Others have criticised China for allowing the rocket's entire 22.5-tonne main-core stage to return to Earth in an uncontrolled re-entry.

China has said it would closely track the debris, and that it posed little risk to anyone on the ground. It has not provided any data to support this claim. 

The Long March 5B blasted off July 24 to deliver a new laboratory module to a Chinese space station that is under construction in orbit.

Social media users in Malaysia have posted video of what some believe to be rocket debris, though this has not been verified. 

In 2020, following an earlier launch, fragments of a Chinese Long March 5B landed on the Ivory Coast, damaging several buildings in the West African nation.