The opposition leader, Bill Shorten, has promised to restore penalty rates in the first 100 days of government and commit $6bn in federal funding for western Sydney rail projects if he’s successful at the next federal election.

In a speech to Labor faithful at the party’s annual state conference in Sydney’s Town Hall on Sunday, Shorten seized on the government’s “disproportionate” tax policy on the day workers’ penalty rates were cut across the country.

Shorten committed $3bn to the Sydney Metro West project, linking the city to Parramatta, and another $3bn to the Western Sydney Rail project, which will connect all of the city to the new airport planned for Sydney’s west.

The New South Wales government has also reserved $3bn for the Sydney Metro West project, which will double capacity between the CBD and Parramatta.

“If I’m prime minister, my government will do our part, we’ll put in our share of the money to make Metro West a reality,” Shorten told the conference. “We have a responsibility to make sure these communities remain great places to live, work and raise your kids.”

He took aim at Malcolm Turnbull’s values, promising the crowd that if elected he would reverse penalty rate cuts – which took affect on Sunday and are estimated to affect 700,000 workers across Australia. Weekend and public holiday penalty rates for staff in the retail, hospitality and pharmacy sectors will drop by 10-to-15%.

“Your penalty rates matter to me just as much as the prime minister’s giveaway to the banks matters to him,” Shorten said. “That’s where the other fellow and I are different.

“I want to send a message to everyone who is spending today washing dishes, or cleaning hotel rooms or stacking shelves. I know you’re working today because you need the money ... And we believe you should be paid fairly for your time.”

On Sunday the ACTU secretary, Sally McManus, was scathing about the cuts, labelling them as “wrong” and unfair. She said they will not only hurt working people but also harm the economy.

“We are going backwards as a country,” McManus told reporters in Melbourne. “The last thing we need is for some of our hardest-working, lowest-paid workers to be dealt out penalty rate pay cuts.

“That is a cut they don’t deserve and can’t afford, coming at a time when working families are struggling with the costs of living.”

McManus said the rate cuts take effect on the same day the prime minister and his ministers get pay rises of up to $10,000 each.

The independent Remuneration Tribunal determined the 2% pay rise, the first in 18 months, for all federal MPs – including the Labor opposition.

Shorten told the conference on Sunday equal pay for women was also a first order economic priority for a Labor government.

In the final NSW Labor conference before both state and federal elections, Shorten also promised $300m in federal funding for parking facilities near public transport amenities.

“This may not sound glamorous, it’s not anything ‘2.0’ - but I reckon when there are practical things we can do to make your life easier, we should just get on and do them.”

NSW opposition leader Luke Foley welcomed Shorten’s funding commitments, saying it was clear Labor was prioritising Sydney’s west.

Day two of the annual conference also saw the party resolve to create a climate change act. The act would provide “a long-term framework for climate change mitigation and adaptation”.

Earlier on Sunday, the former treasurer Wayne Swan labelled Shorten’s ill-fated captain’s call to repeal business tax cuts as an “honest error”.

The opposition leader has backtracked on his pledge to repeal the cuts for companies with turnover between $10m and $50m.

Shorten announced on Tuesday he would repeal the tax cut for businesses in that bracket before internal and business pressure forced him to significantly change Labor’s plan.

“He made an honest error in making that announcement,” Swan told the ABC. “He announced it before it went to the full [shadow] cabinet. That was the only error.”

If Labor wins the next federal election it will keep in place the new 27.5% corporate tax rate for companies between $10m and $50m turnover.

But a Shorten Labor government would repeal the remaining legislated company tax scale reductions.

Swan, who was recently elected ALP president, said the plan targeted foreign companies and big banks, who he believes are going be the biggest winners from tax cuts.

“They drive inequality in our economy. That is bad for living standards, bad for economic growth, and it poisons society,” Swan said.

The small business minister, Craig Laundy, said the two policy positions showed a stark divide between the major parties.

“What we’re arguing for is it that it be consistent across the divide irrespective of size,” he said.

The government hasn’t been able to convince enough crossbench senators to support the full package of company tax cuts, but is continuing to make the case for the cuts.

Laundy said he had no reason to think the numbers would shift after five upcoming byelections.

“At this point in time we can’t get it through, it doesn’t mean you walk way from prosecuting the case and attempting to get support,” Laundy said. “It’s the right thing to do.”