Unions will target the government and large multinationals including ExxonMobil in a campaign on tax avoidance in Coalition-held marginal seats.

The Australian Council of Trade Unions is campaigning to close tax loopholes while arguing for reforms to industrial laws to increase collective bargaining, singling out ExxonMobil and Glencore for tax avoidance and because they are locked in bitter industrial disputes.

The campaign will kick off with radio ads and robocalls in the Queensland seats of Flynn, Capricornia and Forde and Gilmore in New South Wales, leading up to a Senate tax-avoidance inquiry in March.

The ACTU secretary, Sally McManus, told Guardian Australia there was an “overlap between companies avoiding tax and bending workplace laws” to reduce workers’ pay.

According to Australian Tax Office figures, ExxonMobil Australia paid no tax on $6.7bn revenue in the last year while Glencore paid just $44m on $24bn of revenue. The Tax Justice Network has labelled ExxonMobil Australia’s “worst tax dodger” because it has paid no tax in three years on revenues of $24.7bn.

Tax is paid on profits, not revenue, so while neither company has broken the law, the ACTU and the Tax Justice Network argue the use of transfer pricing, deductions and tax havens allows them to avoid tax that should be paid in Australia.

McManus is travelling to Longford in Victoria to support unions locked in a 218-day industrial dispute with ExxonMobil and its contractor UGL CIMIC.

“We think the issue of rich multinationals avoiding tax is a huge issue; it’s robbing us of tax revenue,” McManus said.

“It’s a straight up issue of fairness: the people I’m going to visit [protesting outside their workplace] on the lawns at Longford pay more tax than ExxonMobil and ordinary people are sick of it.”

Tax avoidance is part of a “broader inequality problem” that includes workers not having strong enough rights to get fair pay rises, she said.

McManus said the common element between the two prongs of inequality is the “serious power imbalance” between companies on the one hand and workers and taxpayers on the other.

“Big companies spend resources on lawyers to avoid tax and they’re doing exactly the same with our workplace rights,” she said.

“Governments will only act when there is a counteracting force to the power of big business ... there needs to be a movement of people that demand they pay tax and give fair pay rises.”

According to the Electrical Trades Union, UGL CIMIC set up a shell company, MTCT Services, which then struck an enterprise agreement with five casual workers and demanded 230 Victorian workers sign up to the same conditions.

McManus said the maintenance workers were “pushed out of their jobs by Australia’s biggest tax dodger” and that ExxonMobil proposal amounts to a 30% wage cut for more than 200 families.

The other company in the ACTU’s sites, Glencore, has locked workers out at its Oaky North site for six months, which Labor’s employment spokesman, Brendan O’Connor, has labelled a “disproportionate response” to workers’ industrial bans.

Labor has already promised it will crack down on sham enterprise agreements by requiring workplace deals to be struck a representative sample of the workforce.

This week O’Connor also indicated Labor would consider giving the Fair Work Commission power to arbitrate intractable disputes.

McManus warned that tax avoidance “will be an issue for Malcolm Turnbull and his government” and the ACTU is prepared to escalate its campaign if it did not do more to close loopholes.

“We will not rest until corporations like Exxon and Glencore are paying the tax they really owe,” McManus said. “It is the right of every Australian to a fair share of the profits generated from our natural resources and the labour of Australian workers.”

A spokesman for ExxonMobil said the union protest “continues to provide misinformation” about the dispute.

“Regarding Esso’s maintenance contract with UGL, the specific rates of pay and conditions of employment are a matter between UGL and its employees,” he said.