The pay war between police officers and the WA Government has escalated, with Premier Mark McGowan standing firm amid the threat of ramped-up industrial action.

Police Union president George Tilbury warned the Government that officers would not step back in an industrial dispute it believed was costing the state millions of dollars, indicating action could escalate next week.

But Mr McGowan, in his first public comments since returning from leave, said the Police Union was being unfair to taxpayers by denying the state revenue through its industrial action over the pay dispute.

The Government has offered officers a flat $1,000 pay increase in line with its new wages policy, but the union is adamant it deserves a 1.5 per cent rise.

Earlier this month, the union instructed officers to issue cautions instead of fines for minor violations such as traffic infringements.

Mr McGowan admitted that campaign was taking a financial toll but insisted his cash-strapped Government would not budge.

"I'd urge police officers and the union not to continue with that campaign," he said.

"I don't think it's fair on the public, I don't think it's fair on taxpayers, and I don't think it's productive — and it's not going to change our mind."

But Mr Tilbury defended the industrial action, saying it was set to be ramped up as soon as next week but declining to outline details of what form the escalation would take.

WA Police Union president George Tilbury insists the union's campaign can succeed. ( ABC News: Andrew O'Connor )

"It is not compromising community safety and it is highlighting the level of frustration and anger … because the Premier and the Government do not recognise the hard work police officers do," he said.

"We are prepared to escalate it and that is likely to occur."

The union argues that Labor previously pledged a pay offer in line with the previous government's policy, which would have meant a 1.5 per cent pay increase, but that it later backtracked.

Despite the Government's repeated insistence that it will not change its offer, Mr Tilbury insisted the union's campaign could still succeed.

"Common sense should prevail," he said.