Labor has flagged it will likely support the passage of new free trade agreements with Indonesia, Hong Kong and Peru, but has reassured unions it will seek concessions on labour market access before giving the green light to the new deals.

Guardian Australia understands that the Labor leader, Anthony Albanese, convened a meeting between senior members of shadow cabinet and union leaders in Sydney on Friday to thrash out concerns over the new trade deals, with the unions arguing that the party should block the enabling legislation when it comes to parliament next week.

The meeting was attended by the shadow ministers Richard Marles, Kristina Keneally, Jim Chalmers, Madeleine King, Katy Gallagher, Tony Burke, Pat Conroy and Stephen Jones, with a similar contingent of union leaders present.

While Labor has yet to formalise its position, MPs at the meeting are understood to have outlined arguments in favour of supporting the new trade agreements, but also committed to try to negotiate changes on labour market access and investor dispute clauses before supporting the bill’s passage through parliament.

The negotiation comes as the Australian Council of Trade Unions ramps up pressure on Labor to oppose the legislation, releasing new polling that shows up to 80% of voters in key seats oppose trade agreements that grant foreign workers visas without labour market testing.

The ACTU president, Michele O’Neil, who was at Friday’s meeting, said there were currently 1.4 million people with temporary visas with work rights at the same time Australia was experiencing record low wage growth and high youth unemployment.

“Our message is that we think the government is basically entering into these agreements that trade away Australian workers’ jobs as well as our sovereignty,” O’Neil told Guardian Australia.

“We think it is an anti-jobs policy, we think they are anti-job deals.”

O’Neil said the unions would be lobbying Labor to block the legislation, which would align with the party’s national platform that commits to prohibiting trade agreements that waive labour market testing and include investor state dispute settlement provisions.

Labor had pledged to renegotiate the Indonesian FTA had it formed government.

“We think the Labor platform in relation to trade is a very good platform, and it deals with the key issues that need to be considered in any trade deal,” O’Neil said.

“We think the platform is clear, and we expect the party to act in the interests of Australian workers.

“We think the enabling legislation should be opposed, and that is what we want the Labor party to do, that is what we want the Greens to do, and that is what we want the crossbench to do, and we will be pursuing that over the coming days.”

A report from the Joint Standing Committee on Treaties, expected to be released on Wednesday, is understood to show that Labor members will agree with the majority recommendation to ratify the new FTAs, while raising concerns about labour market access for temporary visa holders in additional comments.

The Greens are understood to have written a dissenting report that outlines concerns about labour market testing, investor-state dispute settlement clauses and human rights abuses in Hong Kong.

The shadow trade minister, Madeleine King, said she would not pre-empt the parliamentary process, the review by the JSCOT committee, nor the processes of the federal Labor caucus.

“These are long-term negotiations and there are parliamentary processes that we have to work through to reach the ratification stages of these agreements,” King told Guardian Australia in a statement.

“Given global trade tensions, it is imperative that Australia diversifies its comprehensive economic partnerships and trade relationships.

“Labor is continuing to speak with stakeholders, within the labour movement and beyond, on these agreements.”