A Labour government would seek to drive up wages by empowering trade unions to negotiate minimum rates of pay across key sectors, starting with adult social care, Angela Rayner will announce on Saturday .

Rayner, Labour’s deputy leader, will set out plans at the party’s annual conference for fair pay agreements aimed at strengthening workers’ bargaining powers, particularly in sectors plagued by low pay and insecure contracts.

The policy, which echoes an approach recently adopted in New Zealand, would introduce government-backed negotiations between unions and employers across an entire sector, rather than firm by firm. These would set minimum pay rates and basic conditions, which would then become a mandatory “floor” across the sector.

“Working people don’t want a handout from a minister sat in Whitehall,” Rayner writes in a Guardian article as Labour meets in Brighton for its conference this weekend.

“Workers want the power to stand up for themselves and to demand a fair share of the wealth that they create. Working people are proud of the work that we do, but we want dignity, respect and a better deal for our class. Tory ministers don’t understand that because they don’t understand working people – they just expect us to know our place and take what we are given.”

Rayner will say the policy would be implemented within 100 days of a Labour government being elected, with adult social care the first sector to be covered.

Frances O’Grady, the secretary general of the TUC, described the plan as a “gamechanger”. “Many of the key workers who got us through this crisis – including our dedicated care staff – are on poverty wages and insecure contracts. Fair pay agreements would help end this injustice and be a gamechanger for millions of working families,” she said.

Labour’s policy forms part of a paper on employment rights being published this weekend, which also includes the promise of a £10-an-hour minimum wage and legislation to ensure workers have full employment rights from day one.

Rayner, who was a homecare worker before being elected to Westminster, says when MPs discuss the social care crisis they rarely consider the implications of low pay in the sector.

“For my old workmates on the frontline a ‘crisis’ means that the care workers who have put their lives on the line throughout this pandemic can’t feed their families and pay their bills. ‘Crisis’ means that there aren’t enough care workers to look after the people who need care.

“This creates a vicious circle of staff vacancies and high turnover rates, which in turn leaves staff at breaking point and devastated because they are trapped in a system that does not enable them to provide the best care for people who need it,” she said.

In New Zealand, when fair pay agreements come into force next year unions will be able to trigger negotiations if they represent 1,000 workers in a particular industry, or 10% of its total workforce. The talks can cover maximum hours, holiday pay and other terms and conditions, as well as hourly pay rates.

Sectoral collective bargaining was included in Labour’s 2019 manifesto. Rayner’s recommitment to the idea underlines the party’s continued close links to trade unions despite fears among some leftwingers about a lurch to the right under Keir Starmer.

Starmer hopes to put a fresh offer for workers at the heart of Labour’s appeal at the next general election. In a lengthy essay published earlier this week ahead of Labour’s conference in Brighton, he stressed the importance of ensuring that effort is rewarded, and promised a “new settlement” between businesses, government and the public.

Labour has criticised the government’s planned increase in national insurance contributions – badged as a health and social care levy – saying it will “hammer” working people.

Rayner secured the title of shadow secretary of state for the future of work in Starmer’s botched reshuffle in May, and has since announced several policies, including a right to flexible working.

She will give her speech to Labour’s Brighton conference on Saturday, fresh from a spiky performance at prime minister’s questions against the deputy prime minister, Dominic Raab.

Labour members are gathering in the seaside resort for five days of debate, likely to be dominated by questions over the direction of Starmer’s leadership. He will give his own keenly anticipated speech – his first face-to-face to party members – on Wednesday.