BEIJING (REUTERS) - China's Tiangong-1 space station is not out of control and does not pose a safety threat, a top Chinese spaceflight engineer said on Monday (Jan 8), after reports that the station was falling towards earth.

The Tiangong-1, or "Heavenly Palace 1", China's first space lab, was launched into orbit in 2011 to carry out docking and orbit experiments as part of China's ambitious space programme, which aims to place a permanent station in orbit by 2023.

Tiangong-1 was originally planned to be decommissioned in 2013 but China has repeatedly extended the length of its mission.

The delay of re-entry into the earth's atmosphere, which China said would happen in late 2017, had led some experts to suggest the space laboratory may be out of control.

Zhu Congpeng, a top engineer at the China Aerospace Science and Technology Corporation, told the state-backed Science and Technology Daily newspaper that the space station was not crashing and did not pose a safety or environmental threat.

"We have been continuously monitoring Tiangong-1 and expect to allow it to fall within the first half of this year," Zhu told the newspaper.

"It will burn up on entering the atmosphere and the remaining wreckage will fall into a designated area of the sea, without endangering the surface," he said.

Re-entry was delayed in September 2017 in order to ensure that the wreckage would fall into an area of the South Pacific ocean where debris from Russian and US space stations had previously landed, the paper said.

The California-based Aerospace Corporation, a non-profit group that works the US government, said the Tiangong-1's re-entry was unlikely to be controlled but was highly unlikely to hit people or damage property, according to a post on its website last updated on Jan 3.

"Although not declared officially, it is suspected that control of Tiangong-1 was lost and will not be regained before re-entry," it said. There may be hazardous material on board that could survive re-entry, it said.

Advancing China's space programme is a priority for President Xi Jinping, who has called for China to become a global space power with both advanced civilian space flight and capabilities that strengthen national security.

Beijing insists that its space programme is for peaceful purposes, but the US Defence Department has said China's programme could be aimed at blocking adversaries from using space-based assets during a crisis.