The Workers (Predictable Terms and Conditions) Act is expected to come into force in Autumn 2024.
It will give workers a new statutory right to request a more predictable working pattern, including agency workers and those on zero hours contracts.
Employers will have to reply to requests within a month.
Acas has created a draft Code of Practice on how to handle requests, which they are asking for employers and employees to review through their consultation.
Acas chief executive Susan Clews said: “Our new draft code will help businesses and workers understand the new law and provide good practice around requesting and handling requests for a predictable working pattern.
“Our code outlines the steps that need to be taken to ensure that requests are handled in a reasonable manner. This includes weighing up the potential benefits and other impacts of the requested change for both sides. Employers need to be aware of the provisions in the law, including who it applies to, and how they should handle these requests.
“We are eager for feedback on the draft Code to ensure it is clear and workable for everyone that will be impacted by the new law next year.”
The code includes guidance on holding a meeting to discuss a request before making a decision, who should be allowed to accompany a worker at meetings to discuss a request and accepting a request where possible.
It also covers only rejecting a request for certain legally allowed reasons, being clear about the reasons for rejection and offering an appeal process.
Clews added that clear official guidence is important for insecure workers who this legislation will often apply to, as they often lack confidence in what their rights are.
She said: "Reliable and accessible channels of dialogue are important. Where workers are on non-guaranteed hours, we know that they can sometimes lack confidence to come forward to ask questions about their working arrangement. Good guidance provides a foundation to support businesses to have open and constructive discussions with workers aimed at finding solutions which work for both sides."
Harriet Walker, advisory and member services director at responsible business network Business in the Community (BITC), said the right to request predictable hours will help employees lead more balanced lives.
Speaking to HR magazine, she said: “Unpredictable working patterns can cause issues for employees when trying to plan their personal and work time in advance, especially those with caring responsibilities.
“We know that many people struggle to balance work alongside their caring responsibilities, with BITC research finding one in five women have left a job as it was too hard to balance work and care.
“Having a clear idea of working hours in advance will allow employees, especially those who are also carers, to make arrangements for the days they are working, which will ultimately prevent them from having to choose between their career and caring."
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However, Paul Nowak general secretary of the Trades Union Congress, said the legislation still leaves the power in the hands of employers.
Speaking to HR magazine, he said: “A ‘right to request’ guaranteed hours is no right at all. Any employer can just say no.
“That’s why Labour’s New Deal for working people is so important. Banning exploitative working practices like zero-hours contracts will give people more control over their lives.
“Unpredictable shift patterns are a nightmare, leaving families unsure of how much income they will have coming in and how they will plan childcare.
“We need to end job insecurity once and for all. Everyone should be entitled to guaranteed hours, with a genuine choice for workers to opt-out, free from pressure from their boss.”