The ACTU Secretary Sally McManus has led hundreds of unionists on a march through Hobart's CBD promising a big fight ahead on workers' rights.

The march and rally provided a launch pad for the union movement's new national campaign 'Change the Rules' which features 12 days of action across the country.

The aim is to push for change in industrial relations rules, particularly around casual work and labour hire.

Ms McManus said many workers in Tasmania were feeling the "sharp end of trickle-down economics" arguing stronger protections were needed to make sure they get a fair go.

"We want to bring back the fair go so working people have jobs they can count on and so our pay keeps up with the cost of living".

Unions Tasmania's Secretary Jessica Munday said many Tasmanian workers were under-employed.

"We know that casualisation is hurting workers, we have a huge problem with under-employment and the Government isn't talking about it"

ACTU President Sally McManus said workers were not getting a fair go. ( ABC News: Cameron Gooley )

"We've had public sector wages frozen at 2 percent for years and a government that's sending a signal to the private sector that they don't have to give decent pay rises," Ms Munday said.

Union member and early education worker Alison Walker became emotional describing her low pay and struggle to make ends meet.

"We need jobs and pay packets that we can rely on. I'm struggling really badly and I'm going back financially every fortnight," she said.

"Its just untenable and it's completely unacceptable in this day and age that we could be professionals and struggling the way we are."

Unions lost a major five-year equal-pay case for childcare workers in the Fair Work Commission earlier this year.

As previously indicated Ms McManus promised the ACTU would be upping the ante on the issues.

"It's now time for us to play a different game. It's time for us to get on the front foot again. Stop defending and start advancing," she said.