After the second attack, the woman surrendered her pitbull, not the one pictured, to Hamilton City Council and it was put down (file photo from Palmerston North pound).

The owner of a pitbull which left one man needing stitches and another surgery has been jailed for a year and four months.

It's the first time a Hamilton City Council dog control prosecution has resulted in a prison sentence, the city council said, and it's "one of the longest national jail sentences ever handed out for a dog attack".

The 51-year-old woman pleaded guilty to two charges and was sentenced in Te Awamutu District Court on December 5.

The dog first attacked in October 2017 when a man was walking past its Campbell St home, the city council statement said.

"The man was attacked from behind and received significant wounds across his head and body, requiring around 100 stitches," it said.

The second man to be attacked was visiting the dog's new home on Clyde St in January 2018.

TOM LEE/STUFF The 51-year-old woman's sentence, handed down in Te Awamutu District Court, is 'one of the longest national jail sentences ever handed out for a dog attack', Hamilton City Council said.

His significant facial injuries required surgery and hospitalisation, the council said.

The owner surrendered her dog to the council, and it was put down.

A legal process started in January 2018 after the second time the dog "viciously attacked", the council said.

However, there were delays in getting the dog owner to attend a hearing, so sentencing wasn't until December 5.

As well as the jail time, the woman has been disqualified from owning dogs.

Council laid charges of dog causing serious injury under the Dog Control Act which can carry a maximum of three years in prison and/or a $20,000 fine.

It's good to see courts enforcing a stronger stance on serious attacks, city council animal education and control manager Susan Stanford said.

"Dog owners need to be held accountable when their dogs cause serious harm. Cases like this send a strong message that it will not be tolerated, and we will prosecute offenders."