Microsoft is planning its biggest round of job cuts in five years as it looks to integrate Nokia's handset unit, Bloomberg reports, citing people with knowledge of the company's plans.

The reductions, expected to be announced as soon as this week, could be in the Nokia unit and the parts of Microsoft that overlap with that business, as well as in marketing and engineering, the news agency reported. 

Since absorbing the handset business of Nokia this spring, Microsoft has 127,000 employees, far more than rivals Apple and Google. 

Wall Street is expecting chief executive Satya Nadella to make some cuts, which would represent Microsoft's first major layoffs since 2009.

The restructuring may end up being the biggest in Microsoft history, topping the 5,800 jobs cut in 2009, the report said.

Some of the job cuts will be in marketing departments for businesses such as the global Xbox team, and among software testers, while other job cuts may result from changes Mr Nadella is making to the engineering organization, Bloomberg reported.

Microsoft employs more than 1,200 people in Ireland.

Last week, Mr Nadella circulated a memo to employees promising to "flatten the organization and develop leaner business processes" but deferred any comment on widely expected job cuts at the software company.

Mr Nadella said he would address detailed organisational and financial issues for the company's new financial year, which started at the beginning of this month, when Microsoft reports quarterly results on 22 July.