The British Chambers of Commerce says firms will want to see more detail on the timeline for Employment Right Bill reforms announced by Labour yesterday - and also guarantees of no surprises.
BCC deputy director of public policy Jane Gratton said: "This is the biggest shake up of employment law in decades. These are huge changes and businesses must be engaged and supported on them every step of the way.
"If the right balance is struck, then we have the potential to get more people into work and boost economic growth. But if the process is mishandled, there is a danger these changes could have the opposite effect.
"It is important to stress that the legislation we are seeing is a starting point. It is setting out a framework, and the detail and the mechanics of how this will operate will still need much further consultation.
"Many of these changes are going to need secondary legislation and it's unlikely we'll see major changes to business practices until 2026.
"But firms will want to see more detail on the timeline for these reforms and guarantees that there will be no surprises.
"We all recognise that a thriving workforce is more productive and that drives growth. We will continue to work with Government and the unions to ensure that a balance is reached. One that encourages businesses to recruit and has the right support for employees."
The major overhaul of workers' rights will mean millions of people will be able to get sick pay from the first day they are ill and claim unpaid parental leave as soon as they start a job.
The Government is seeking to be pro-worker and pro-business and striking that balance means that much of the detail is still to be decided.
As part of the plans, the existing two-year qualifying period for protections from unfair dismissal will be removed.
Ministers have said this will benefit about nine million workers who have been with their current employer for less than two years.
However, workers will be subject to a proposed nine-month probation period when they can still be sacked without a full process.
If a worker is sacked within those nine months, it is unclear under what circumstances they can make a claim for unfair dismissal and when they cannot.