The Society for the Prevention of Cruelty to Animals (SPCA) is preparing a case against a person believed to have cut off an eight-week-old Tauranga puppy's ears with a pair of scissors.

SPCA inspector Jason Blair said he would have completed a prosecution file by next Wednesday and would give it to a solicitor, who would decide whether the case was strong enough for it to go to court.

"We don't put these together unless we think we've got enough to carry it through," Mr Blair said.

Mr Blair did not wish prejudice court proceedings by disclosing further details of the case.

"It's still a work in progress and it's probably going to take some time but if we get the right outcome it doesn't matter how long it takes."

The case of the puppy called Trooper caused public outcry when images of its horrific injuries were circulated in the media in November.

A $1000 fine was offered for information which led to a successful prosecution, thanks to donations from members of the public.

The offender could face up to five years imprisonment or a $100,000 fine if convicted.

Tauranga SPCA staff kept in regular contact with Trooper, who was doing really well in his new family home, Mr Blair said.

"He's looking really good."