Unions angry about stagnating wages are planning their biggest campaign since the "Your Rights At Work" push that helped topple John Howard.

The ACTU is planning a series of mass marches around the country in the largest demonstration of union power since the 2007 anti-Work Choices campaign.

"People around the country are ready to take action to change the rules and win more secure jobs and fair pay rises," ACTU secretary Sally McManus said on Wednesday.

"They know big business has too much power, and they know that when working people join together we are mighty and unbreakable."

The marches will be held in 18 cities and towns across Australia in April and May, starting in Melbourne on April 17.

"Anyone who wants to live in a better, fairer country, who wants more secure jobs and fairer pay rises, should attend these events and join the movement for change," Ms McManus said.

Labor replaced Work Choices after the 2007 election, but the Fair Work system has come under fire for not delivering wage growth while company profits increase.

The ACTU absolved the former Labor government for the problems that have faced Australian workers since then.

"Changes in the Australian economy and workforce since the global financial crisis of 2008-2009 were never envisaged by those who drafted the Fair Work Act in 2008," the ACTU executive said in a resolution.

"The need to change these laws is urgent."