Police shot a suspect in the elbow early on Friday morning, after he told them he was armed.
The 34-year-old man was hit in the elbow, and is in a stable condition in hospital.
The incident began around 1:15am when police saw a car driving "slowly and erratically" in Nelson. When the vehicle pulled over, the driver got out and ran to a house on Waimea Rd.
A dog handler was sent in, but backed off when the suspect said he was armed. Police entered the property after backup arrived.
"The man has approached police as they entered the property and challenged police," said Tasman District Commander Supt Mike Johnson.
"He was carrying what police believed to be a firearm at the time. The police dog was deployed and police fired a shot as the man continued threatening police."
They provided first aid as they waited for the ambulance to arrive.
Police have yet to recover the suspected firearm, and charges are yet to be filed. A full scene examination will get underway "in due course".
One of the police officers was bitten by a dog. It's not clear if this was the police dog or another dog on the property.
"The man in this situation was known to police and made multiple threats to harm the police who attended this incident," said Supt Johnson.
"While no police officer expects to have to use potentially lethal force when they begin their shift, it is a very real risk and our staff are well trained to make the right tactical decisions based on the information they have at the time."
The Independent Police Conduct Authority has been advised of the incident.
Newshub.