On this International Women's Day, I'm thinking of Erin, Linda and Margarita.

Erin works in retail. She's not on big dollars, but after working hard and putting money away for a decade, she's just bought her first home.

The Fair Work Commission's decision to cut penalty rates for retail workers – supported by the Turnbull Government – will make it a lot harder for Erin to meet her mortgage payments.

"I saved so hard and so long to buy a house, exactly what the government wanted," she says. "Now they're taking away a significant portion of my income and potentially my ability to pay off my mortgage."

Linda's a single mother who used to rely on social security, but has since re-skilled to become a chef.

Sundays are the busiest day of Linda's week. She relies on the extra money as it helps her pay the rent for the family home – which eats up more than half her wage.

Margarita is a mother of two. She works at a hotel on Sundays. She gives up time with her family, to provide for her family.

"Everything is getting more difficult," Margarita says. "The bills go up, so why is our wage going down?"

Every year on International Women's Day, we celebrate the progress we're making towards gender equality, and we challenge ourselves to do better and to do more.

This year there's an urgent and obvious task for us. It's staring us in the face. We need to stop the cuts to penalty rates.

Women like Linda and Erin make up the majority of the retail and hospitality workforce, so cutting penalty rates in these industries means cutting women's wages.

The Prime Minister is fond of quoting Mao Zedong's saying that women "hold up half the sky". But Australian women aren't getting half the pay. And unless the Turnbull government acts to stop the penalty rate cuts they'll be going backwards.

The gender pay gap in Australia is currently 17 per cent, even getting to this point has taken far too long. This cut to penalty rates will make the gap wider, it will take Australia backwards.

Not everything can be fixed in Canberra, or by parliament – but this can.

For Labor, equal treatment for women isn't just an aspiration we mention one day of the year – it's an everyday, 365 days a year priority.

Yes, progress is hard. Yes, change can be slow. Some of the cultural shifts we need will take us a generation.

But when there are things the parliament can do, right now, that will protect women, how can the Liberals and Nationals and One Nation sit on their hands?

I have legislation before the parliament to reverse the cuts to penalty rates, and change the rules so that the Fair Work Commission can't cut workers' take home pay in the future.

It's a simple fix to a problem that no one saw coming.

In defending his support for the pay cuts, the Prime Minister likes to criticise me for previously saying I would support the Fair Work Commission's decision.

He is right. I did say that. In my wildest nightmares I didn't think the Commission would ever decide to cut wages and leave low-paid workers worse off – I was wrong.

Now there's a simple choice. Do something to protect the take-home pay of workers and prevent the gender pay gap from growing even further. Or do nothing.

Malcolm Turnbull has decided to do nothing. He says he supports the decision to cut penalty rates. I don't. He says he supports the cuts. I don't. He says he won't fight the cuts. I will.

The Parliament has the power to stop this pay cut that will hurt hundreds of thousands of women. This cut to wages is the thin edge of the wedge for the penalty rates of all working women. It needs to be stopped now.

On International Women's Day, I'm proud to say Labor is standing up for Erin, for Linda, for Margarita, for every other Australian woman who relies on penalty rates to make ends meet.

We always will.

This opinion piece was first published online via the Age on Wednesday, 8 March 2017