Malcolm Turnbull argues the decision to cut Sunday penalty rates for about 600,000 workers is complex.

So too is the way he tries to explain it.

“Let’s take an example of a worker who only works on public holidays, right?” the prime minister told Sabra Lane on ABC radio on Thursday.

“Even if you phased it in over 10 years, they would still – or five years, they would still have a reduction although, of course – and again this is why it’s complex – the base rate is going to be increasing. ”

Get it?

On the not-so-helpful advice of Eric Abetz, the man he dumped as employment minister, to grandfather the Fair Work Commission’s ruling so that it only applies to new employees, Turnbull was just as obtuse.

“Well, it depends what you mean by grandfathering?”

The commission would consider submissions, including one from the government about “technical issues”, on how its decision should be implemented.

“We’re being asked in paragraph 2019 in Chapter 11 of the report to make a submission on how take-home pay orders can be applied – again it’s a complex area,” Mr Turnbull later told reporters.

The likelihood, if the commission sticks to past practice, is that it would be phased in over a period of years.

“And of course what that means is that as the rest, as the base pay goes up every year with the minimum wage, so, you know, 2.4 per cent or whatever it is – that’s what it was last year – every year the employee’s overall pay packet increases and offsets the phased-in reduction in penalty rates.”

Except that overall wage growth last year was just 1.5 per cent, according to the latest national accounts, and the outlook for the year ahead is not much better.

As for the workers impacted by the commission’s decision?

They would be pleased to know that “the facts are it was a decision of the Fair Work Commission, not a decision of the government, and that was quite appropriate”.

Senator Abetz says his approach would ensure that “no worker is worse off” while allowing new opportunities for the unemployed and especially for young unemployed people.

“It would mean no existing worker would have their income or household budget adversely impacted while supporting small business and assisting the unemployed,” he said.

Deputy Labor leader Tanya Plibersek said high turnover in the sectors affected meant grandfathering penalty rates wouldn’t work.

“I’m not sure how long that would actually protect workers,” she told ABC radio, using the example of someone moving from one franchise outlet to another.

“Because they’ve moved 5km up the road they take a $77-a-week pay cut? That’s not fair,” she said.

Employer lobby group the Australian Chamber of Commerce and Industry wants the changes to come in as soon as possible.

“We now need to focus on a transition, and we believe that should happen as quickly as possible so we can see the benefits,” chief executive James Pearson said.

Unions are opposed to any changes to wages, even if they are grandfathered, and wants the government to intervene.

Access exclusive analysis, locked news and reports with Inside Retail Weekly. Subscribe today and get our premium print publication delivered to your door every week.