Labor’s left faction is beginning to raise its voice about the plight of children on Nauru – concerns have been raised at a meeting of factional convenors and union bosses, and there has been a public expression of unease from the member for Batman, Ged Kearney.

With Bill Shorten set to move his troops on to an election footing on Sunday with a second headland speech in Sydney’s west, a meeting of left powerbrokers on Saturday heard concerns about the condition of children on Nauru, and also continuing anger about the party’s support for the trans-Pacific partnership trade pact.

In response to a poll published by Guardian Australia on Saturday, which found that a clear majority of voters in the electorate of Wentworth wanted children on Nauru to be brought to Australia for medical assessment, Kearney said on Twitter that the status quo was unacceptable.

What’s happening? This is happening. We can’t keep sick and dying children away from the medical care they need #kidsoffnauru https://t.co/CdVUgld4Pa — Ged Kearney (@gedkearney) October 5, 2018

Anger about the ALP’s support for the TPP-11 trade pact dominated Saturday’s discussions in Sydney, and key union leaders, including Paul Bastian from the Australian Manufacturing Workers Union and Michael O’Connor from the Construction, Forestry, Mining, Maritime and Energy union were critical of the parliamentary party for signing on to the deal.

Officials felt they had been ambushed by the shadow minister for trade, Jason Clare, and the party leadership, citing inadequate consultation before Labor’s decision to sign, and there was a desire expressed to activate right-wing unions to increase opposition to the trade agreement.

There was also a strong view that Labor should take a proactive position on removing children from Nauru, after a recent public intervention by the Australian Medical Association and other medical groups characterising conditions on the island as “a humanitarian emergency requiring urgent intervention”.

There are about 100 children on Nauru, many in long-term detention. Doctors have appealed for a large cohort to be removed because of a deterioration in their physical and mental health. There have been a spate of horrific cases in recent months involving minors.

Medical sources on Nauru have told Guardian Australia there are at least 20 children in the Australian-run regional processing centre 1 (RPC1) on “food and fluid refusal” and at risk of permanent harm or death.

Other issues canvassed at Saturday’s left-faction meeting include a desire that Labor be more proactive on the Uluru Statement from the Heart, and more muscular on economic policy – concerns were raised that the shadow treasurer, Chris Bowen, was more focused on bringing the budget back to surplus than on social spending.

Conveners were asked to put together a paper on the economy before a full caucus meeting this month. The factional meetings are part of the prelude to the ALP’s national conference in December, where a meeting-floor stoush over the trade platform now seems inevitable.

With federal parliament not due to resume for another week, the prime minister, Scott Morrison, and Shorten have been out campaigning.

Morrison spent the last week in Western Australia, where the Liberals are in political trouble, and is in Tasmania over the weekend for the state party conference.

Shorten announced a significant policy on early childhood education in Melbourne this week, extending pre-school to three-year-olds, and will be in western Sydney on Sunday to launch what he is terming his “fair go action plan” at the Revesby Workers Club.

Labor will mobilise a field campaign on Monday in 100 federal electorates around the country, in preparation for the federal election, expected in the first half of next year.

The looming byelection in Wentworth will be an important litmus test of community sentiment, and seat polls suggest it will be an uphill battle for the Liberals to retain it, despite the current margin of 17%.

In a statement issued before Sunday’s speech in western Sydney, Shorten said he had conducted 80 town hall meetings during his time as opposition leader “and it’s these direct conversations I’ve heard with Australians that have shaped this plan”.

“People telling me everything is going up except their wages, that they are waiting longer for elective surgery, that they are worried about the future we’re leaving for our children,” he said.

“I think the Australian people deserve the next election to be a contest of policies and ideas. A national debate that isn’t about tonight’s news or tomorrow’s papers, but the Australia of 2030 and 2040.”