Christchurch is among a list of cities more likely to be hit by a Chinese space station that is spiralling towards the earth, with impact expected within the coming weeks.
In 2016, China admitted it had lost control of the 8.5-tonne Tiangong-1 module and was helpless to stop it plummeting through the atmosphere.
The station, potentially carrying highly-toxic substances, is estimated to hit the earth between March 24 and April 19.
A map produced by Areospace shows the motion of the station as it circulates towards earth. The points of 43° north and south are where it levels out before heading back in the other direction.
This means it spends a longer amount of time at those two latitudes than at any other latitude on its spiral down. Christchurch lies at this point in the south.
A number of highly populated cities are also situated along this narrow strip, including Toronto, Toulouse, Sapporo, Milwaukee and Trelew in Argentina.
The chance it impacts Christchurch is still only a small likelihood as it moves diagonally around the earth.
The station is carrying a "highly toxic" corrosive chemical on board, and hundreds of kilometres could be affected by the poisonous rain of debris.
"Potentially, there may be a highly toxic and corrosive substance called hydrazine on board the spacecraft that could survive re-entry," the US Aerospace Corporation warns.
"For your safety, do not touch any debris you may find on the ground nor inhale vapors it may emit."
The US Environmental Protection Agency warns hydrazine is known to cause seizures, coma and death.
"Symptoms of acute (short-term) exposure to high levels of hydrazine may include irritation of the eyes, nose, and throat, dizziness, headache, nausea, pulmonary edema, seizures, coma in humans," it says.
"Acute exposure can also damage the liver, kidneys, and central nervous system. The liquid is corrosive and may produce dermatitis from skin contact in humans and animals."
Launched in 2011, the Tiangong-1 station was seen as a symbol of Chinese ambitions in space, and its strength as a global superpower.
It could hit earth from as early as Saturday.