Ammonium nitrate is primarily used as agricultural fertiliser, but it is also a potent explosive.
In 2020, 218 people were killed in Beirut, Lebanon, after 2750tonnes of poorly stored ammonium nitrate exploded.
WorkSafe energy and public safety head of high hazards Darren Handforth was aware a ship carrying ammonium nitrate had been unable to unload at New Plymouth because of poor weather.
The ship is understood to be the Vanuatuan-flagged Atlas Wind, which left the Leith St Wharf at 7.30pm on Wednesday.
"We were advised on Wednesday afternoon that the ship had been sent to Dunedin to unload," Mr Handforth said.
A warehouse in Sturdee St was used to temporarily store the 1200kg bales before they were transported to their final destination.
"Although WorkSafe has not reviewed specific plans for this transit, we intend to review the emergency response plan and will take appropriate action if required."
Ellis and Co communications managing partner Jackie Ellis — speaking on behalf of Move Logistics, which operates the Sturdee St site — said the company had decades of expertise in moving dangerous goods and strong safety processes.
The warehouse was a certified-approved transitional facility.
The transit process often took "less than 24 hours, as in this case".
She did not respond to queries about the amount of ammonium nitrate which was stored at the site.
The Otago Daily Times understands it was about 200tonnes.
A Dunedin City Council spokesman confirmed the company was operating in accordance with all relevant sections of the district plan rules.
Ammonium nitrate was able to be stored for up to 72 hours in the industrial area where the warehouse was located.
