Google has raised its cost estimates for its job cuts at Motorola Mobility and warned that there will be significant costs related to further restructuring, reports Reuters.

The severance charges being paid to employees is 9 percent higher than first forecast at US$300 million. With the exit from facilities and some markets, this may rise by another US$40 million, says Google.

In August, Google announced it would slash Motorola Mobility’s headcount by 20 percent – equivalent to 4,000 jobs – as it focused the handset maker on fewer markets and a slimmed down product portfolio.

A Google statement said Motorola has refined its planned restructuring and expects these to also have an effect on operations outside the US. A Google spokeswoman said no more job cuts will be announced.

Google completed its US$12.5 billion acquisition of Motorola in May as it looked to bolster its patent holdings to compete with the likes of Apple and Samsung. However analysts have questioned if Google has a concrete plan for the mobile hardware maker itself.

According to Google's most recent quarterly results Motorola Mobility lost US$233 million in its first six weeks under Google, while the New York Times said the business was unprofitable for 14 of the past 16 quarters.

Motorola recently launched its Intel-powered Razr i smartphone in September and refreshed its DROID line-up with three new devices.