GENEVA, May 29 (Xinhua) -- International Labour Organization (ILO) Director-General Guy Ryder said Wednesday here that some 44 heads of state or government are expected at its June 10-21 centenary conference when it will discuss a new document on the future of work.

Among the leaders expected to attend are South African President Cyril Ramaphosa and Sweden's Prime Minister Stefan Lofven, who co-chaired an ILO report on the future of work.

That report about the effects of the fourth industrial revolution on society was presented in Geneva in January.

Among other leaders expected to attend, according to the ILO, are French President Emmanuel Macron, German Chancellor Angela Merkel and Turkish President Recep Tayyip Erdogan.

UN Secretary-General Antonio Guterres will address the closing session of the conference.

"These are going to be changes in the nature of work," said Ryder, noting that there have been massive changes in work such as globalization, climate change, demographics, whether aging societies or for those with many young people.

"We want to deal with the changes on the future of work in a hard-nosed way," said the ILO chief, noting that the centenary is not aimed at being a celebratory event but will keep focused on the UN Sustainable Development Goals (SDGs).

He said one of the issues that the ILO convention will act upon is violence and harassment in the workplace and a global treaty aimed at it is expected next month, but with some "tricky" issues remaining.

Ryder said, however, "In the light of the progress previously made, in light of the importance of the subject matter, I am very confident that the conference will adopt a convention and recommendation."

The ILO's new treaty will be a significant statement of intent and guidance in the future, and the role of the broader multilateral system and its role for work, said the head of the ILO.

"We hope it will be agenda setting...but it is not a binding document," said Ryder.

More than 5,700 delegates - workers, employers and government representatives -- from ILO's 187 members are expected to attend here the ILO centenary conference next month.