The Western Australian government's election commitment to end puppy farms probably won't be realised this term, with the opposition saying the legislation is "messy" in its current form.
The proposed changes to the Dog Act include mandatory desexing, breeder registration, a centralised registration system to identify every dog and puppy, and transforming pet shops into "adoption centres".
The Nationals have proposed three amendments to the planned legislation and the opposition is going to suggest another, all related to increased bureaucratic and cost burdens.
Premier Mark McGowan says he does not understand "why the Liberal party is supporting cruelty to dogs".
"I don't get where they are at," he said on Wednesday.
Opposition deputy leader Bill Marmion said there was broad support for the bill but it needed a fair amount of work and did not even define what constituted puppy farming.
"It's a bit of a messy bill," Mr Marmion told AAP.
He said the pure-bred owners' association Dogs West wanted exemptions while the WA Local Government Association was circumspect as it was concerned about cost recovery for the additional administration.
"No one likes puppy farming.
"It can be quite a lucrative business.
"The issue is how they're cared for."
Mr Marmion said he doesn't expect the Labor-dominated lower house to agree to the amendments and even if it does, the legislation is unlikely to reach the Upper House before the state election in March.