It’s understood the Marshall Government will introduce legislation to establish a local government rate-capping scheme into parliament next month, with the Opposition reserving its position until it has seen the detail.

Rate-capping is one of several policies currently under review by the ALP under Malinauskas, with the party thus far only committing to oppose the deregulation of shop-trading hours – albeit with a possible exemption for Sunday morning trade.

But Labor’s 2018 state policy platform, ratified by last year’s annual convention of the party, unambiguously commits the ALP to “oppose rate-capping and measures that undermine the fiscal independence of local councils”.

The internal document, seen by InDaily, declares that councils provide “a vital voice for local communities and deliver an important range of services for their communities”, and that “Labor believes councils must be well-resourced, self-managing, representative and responsive to their communities”.

Labor insiders are adamant the party cannot go back on a commitment in its policy platform without seeking the assent of state convention.

“If it’s in the platform it can only be changed by another convention – whether a special one called for [that purpose] or an annual convention,” said one party source.

With the Greens and SA Best likely to oppose the Government’s legislation, Labor’s policy decision is expected to make or break the bill in the Upper House.

There is a view within the party that it could be open to a compromise amendment – which would see a cap imposed, but substantially above the inflation rate – but even this would represent a marked shift from the unambiguous commitment enshrined in the policy platform.

It’s understood the relevant ‘Democracy and Good Governance’ clauses, including the commitment to oppose rate-capping, were passed unanimously at the convention.

While Malinauskas is conducting a broad policy review and wide-ranging consultation, a missive in the policy document from the Platform Committee, then chaired by MP Chris Picton, states: “This platform is the product of wide consultation both within and beyond the party.”

“Therefore, it should be no surprise that it reflects the passion, purpose and ambitions of our members and supporters,” the document reads.

In response to questions from InDaily about whether a change to Labor’s rate-capping policy would require a special convention, Malinauskas said in a statement: “It’s entirely appropriate after an election loss to reflect upon the party’s policies.”

“But before there can be any further discussion regarding rate capping, we need to see the Liberal Party’s legislation,” he said.

However, insiders say there’s a lot of disquiet about even the prospect that the endorsed party policy could be watered down or even jettisoned.

InDaily reported this week that two MPs – from both right and left factions – had already publicly spoken out against rate-capping despite the policy being under review.

Within the broader labour movement, the campaign to oppose the Liberal legislation is being driven by two unions with significant member representation in local government – the Australian Services Union and the Australian Workers Union.

ASU state secretary Abbie Spencer – a member of the ALP’s state executive – told InDaily the union was “keeping the discussions open” with the party.

“My understanding is it’s a pretty serious matter to go against party platform,” she said.

“There isn’t a mood within the party to change the party platform.”

AWU state secretary Peter Lamps said his union represented around 1800 local government employees – around a third of their membership – across the state.

“What we’ve seen interstate – and especially in the regions – is that rate-capping means a reduction in jobs,” he said.

“Our role will be to ensure that the wider communities understand what rate capping will mean… as far as provision of services, both metropolitan and regional.

“We’ll be mobilising our members over the next few weeks and reaffirming those conversations with our members… you’ll probably see that starting to galvanise over the next two to four weeks.”

He said that would likely take the form of “mass meetings and the like”.

Lamps said the current debate around local government spending – including a fresh inquiry by Ombudsman Wayne Lines into the use of corporate credit cards at Onkaparinga Council – was more of a “governance issue”.

“It’s more about having a strong cop on the beat,” he said.

“If we look at some of the matters affecting local government at the moment – even if you had rate-capping, it wouldn’t address those issues.”

He favoured a focus on “strong governance… not only in the Local Government Act, but beefing up the ability for ministers to intervene”, as well as the Auditor-General and Ombudsman.

He said resolving those governance issues would “flow through to lower council rates”.

“It appears to me there’s a lot of waste,” he said.