From October, employers will be required to inform workers of their right to join a trade union, while new legislation will also introduce a right to time off for trade union equality representatives.
Changes to unfair dismissal protections also ranked highly, with 23% of employers citing the reduction in the qualifying period from two years to six months as a key concern.
The workplace advisory body said it handled more than 150,000 early conciliation notifications during the year.
Among small and medium-sized businesses, 40% of workers said their organisation lacked these skills.
46% of large businesses said they were likely to make redundancies.
The Acas poll found 24% agreed that international media attention on sexual harassment had a positive effect in their workplace.
Employers said the most common reason for absence was minor illnesses like coughs, colds and flu, with 62% stating this.
The survey showed only 32% said their employer effectively trained managers to make reasonable adjustments for neurodivergent staff.
She starts on 1st April 2026, taking over from Clare Chapman, who has completed two terms as chair.
Employers put new paternity leave rights from day one of employment as their third priority, with 28% choosing it.
As part of the agreement, CIPD members will gain access to a new jointly developed learning programme, 'Working effectively with trade unions: Acas in collaboration with the CIPD'.
The consultation follows the introduction of the Employment Rights Act 2025, which received Royal Assent on 18th December 2025.