An ambulance responding to a patient's emergency medical alarm was sent to the wrong district after an embarrassing systems botch up - sparking an apology and investigation by officials.
But the error ended up prompting a bomb scare when ambo officers discovered a rocket-propelled grenade.
Emergency services were delayed for the Freyberg Street, Feilding medic alert user after an ambulance was mistakenly sent to a Freyberg Street house in Levin.
The serious lapse was made when St John received a medical alarm call about 4.30pm on Monday. St John assistant operations director Grant Pennycook said an incorrect system transfer saw an ambulance wrongly dispatched to Horowhenua instead of Feilding - 65km in the wrong direction.
"The initial response arrived on scene in Levin at 4.39pm and a second vehicle arrived at the medical alarm response in Feilding at 5.08pm.
"As soon as St John was advised of the correct address an ambulance was sent and the patient was treated and transported to hospital."
He refused to provide details about the patient or their condition, citing privacy concerns.
On arrival at the Levin address, the ambulance officers gained entry into the house through a window searching for the patient. While inside they came across a rocket-propelled grenade (RPG) inside a glass cabinet and called police who secured the premises.
The New Zealand Defence Force Wellington Bomb Disposal Unit attended the scene and removed one of the bombs.
A police spokesperson said one of the bombs had been classified as safe, while the other had to be removed and disposed of.
Levin man Barry Gill who lives at the address and owns the RPG, said he was annoyed at the mistake St John had made.
"I was at work when I received a call from police. The ambos offered no apology and the guy was actually quite rude; they had searched through our drawers as if they were looking for a good enough reason to be here."
Mr Pennycook denied this took place and said St John were sorry for ending up at the wrong house.
"We apologise for this system interface error and are currently investigating how this happened.
"St John applaud the quick thinking of the officers who responded to the Levin address where the explosive device was located; their quick thinking has ensured public safety."
Mr Gill said they'll never know if it was worth it or not.
"They took it away to destroy it; they said you wouldn't be able to tell whether it was live or not."
The RPG was originally bought from England as a gift for his partner and had been sitting around for "quite a few years".
"It's not only a waste of a few hundred dollars but it has also created rumours in our street all because someone else came to the wrong address."
A St John Ambulance report to the Ministry of Health released earlier this year highlighted 30 serious incidents. One occasion included a case where staff were unable to find an address, with the patient dying before they got there.
- Manawatu Guardian