In the Midland Magistrate's Court last week, the Department of Local Government and Regional Development (DLGRD) withdrew the charges.

"The charges were withdrawn in light of technical legal difficulties which came to the department's attention at a late stage," a Department for Local Government Animal Welfare Unit spokesman said.

"Those difficulties are not expected to recur in future prosecutions."

The charges were bought against the company after members of the organisation Animal Rights Advocates (ARA) made a complaint about the treatment of some of Westpork's animals at the Mindarra II piggery in Gingin nearly three and a half years ago.

A subsequent raid took place to investigate whether the piggery's operators had breached the 2002 Animal Welfare Act.

It's understood that the investigation into the Gingin piggery was started as early as 2007 following claims that some pigs at the facility had eaten others that had died in their pens.

ARA co-ordinator Jonathan Hallett said animal welfare laws weren't sufficient enough.

"ARA believes this is another demonstration of the pig industry's inability to regulate itself and the government not taking the interests of animals seriously," Mr Hallett said.

"Westpork is WA's largest producer of pork and provides up to 150,000 animals per year to WA's pork supply.

A spokeswoman for Australian Pork Limited (APL) said the APL was not involved in this case and therefore was not in the position to make any comment on the case."

A spokesman for the West Australian Pork Producers' Association (WAPPA) said the association had not been advised of the circumstances in which the charge was dismissed and therefore declined to comment.

Mr Ferguson also declined to comment on behalf of Westpork.