Arthur Rorris has promised Bust the Budget will build "the biggest mass movements this country has ever seen".
Mr Rorris, the South Coast Labour Council secretary, said a big public campaign was brewing to oppose the Abbott government's unpopular budget measures.
"It amounts to a declaration of class war. How else do you interpret a budget that protects the big ends of town but punishes everybody else?" he said.
Mr Rorris, who chaired the Wollongong meeting at the same time as one was held in Sydney and protesters gathered in Melbourne, said the campaign would far surpass the vocal fight against WorkChoices legislation in 2005.
"Maybe the government hasn't done its numbers right, because if they think we'll fight this just as a union campaign they'll be sadly mistaken," he said.
"This will be a people's movement, the likes of which this country hasn't seen for a long time."
Mr Rorris placed the onus back on the government to provide jobs.
"What they want to do, in a very insidious way, is blame the unemployed, but we ask how many jobs have they created in our region? Where are their plans to create jobs?" he said.
The Bust the Budget campaign is just gaining steam. But Mr Rorris revealed plans including an Occupy Wall Street-style sit-in.
"We are looking at a permanent display of resistance and defiance to the budget, in a public place," he said.
"There's only one way for the campaign to go, and that's up."