Motorola Mobility is to slash 20 percent of its workforce as its new parent Google seeks to refocus the handset-maker on fewer markets and a slimmed down product portfolio.

Some 4,000 jobs will go in total – a third in the US – while a third of its 94 offices worldwide will be shuttered. Google closed its US$12.5 billion acquisition of Motorola in May, a deal motivated in large part by Google’s need to get its hands on Motorola’s rich portfolio of wireless patents.

Dennis Woodside, Motorola’s new chief executive (installed by Google), confirmed the restructuring plans in an interview with the New York Times.

He said that the vendor also planned to cut the number of devices Motorola makes from the 27 it launched last year to just a few high end models.

“We’re excited about the smartphone business,” said Woodside. “The Google business is built on a wired model, and as the world moves to a pretty much completely wireless model over time, it’s really going to be important for Google to understand everything about the mobile consumer.”

While Motorola was once a market leader, it has been eclipsed in recent years by the likes of Apple and Samsung in the smartphone space – despite being an early backer of Google's Android mobile OS.

The handset business lost US$233 million in its first six weeks under Google, according to Google's latest quarterly results. According to the New York Times, the business has been unprofitable for 14 of the last 16 quarters.