Labour is under fire from its fiercest of allies - the unions frustrated at the lack of Government progress on creating sector-wide fair pay agreements.
A proposal has been with the Government since December but hasn't seen the light of day 10 months on.
Supermarket workers are underappreciated and undercompensated, according to First Union delegate Connor Cooke.
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"[It's] stressful and very taxing. I think a lot more than some people realise," said Cooke.
He wants unions to negotiate fair pay agreements across all supermarket workers - something Labour promised but hasn't yet delivered.
"It's frustrating to see the Government dragging its feet over something it promised quite loudly," said Cooke.
Fair pay agreements would set minimum pay and conditions across entire industries. Unions say cleaning, security and supermarkets should be first in line.
The idea is at the core of Labour Party policy.
"There's frustration. I think there's a bit of impatience. The report has been with the Government since December last year," said New Zealand Council of Trade Unions [CTU] President, Richard Wagstaff.
Union members voiced that frustration to Deputy Prime Minister Winston Peters on Tuesday, who opted out of the singalong, using his speech to give unions stick for striking under this Government.
"We are being attacked by the union movement in this country," said Peters.
Prime Minister Jacinda Ardern is far more in tune with the unions, but still on the defensive - telling union members to sit tight.
"Big bold moves we haven't worked to build public support around... sometimes, they can be lost," said Ardern.
The Prime Minister has promised an announcement on fair pay soon.
Winston Peters likes to refer to New Zealand First as the handbrake on the Government and some of Labour's more staunch Labour Party policies.
However, upsetting the unions - even though New Zealand First might not care too much - is truly risky for Labour.