Nowak was speaking yesterday at the CIPD Annual Conference in Manchester, about the role of unions in the debate about the need for stronger employee voice in an organisation.
He called for workers to have more influence over the long-term strategic direction of businesses.
Last month TUC general secretary Frances O'Grady said having workers sit on company boards would ensure "reasonable" levels of executive pay, and that corporate governance laws in the UK were "missing a trick" by preventing workers sitting on remuneration committees.
"This is not a radical idea, in the EU 19 countries have provision for worker representation at board levels," said Nowak. "It's about tapping into that expertise that's in the shop floor of different parts of the organisations that can help inform board decisions."
Nowak called for HR to engage with union representatives on all issues, not just the "bread and butter" ones such as, pay, pensions and terms and conditions.
"HR must help employees gain a stronger voice over things like workplace change, reforms, innovations and help support these processes rather than view them as a barrier to change," he said.
"There are a lot of examples across the public and private sector where employers and unions have worked together to make sure the voice is heard and let them make decisions to help the long-term sustainability of the company."