Microsoft signalled a fresh onslaught against arch-rivals Google and Sony yesterday as it predicted a sharp and unexpected jump in costs in the coming quarters to accelerate its push into sectors such as videogames and online services.

"Clearly we have decided to aggressively invest next year in a number of areas," said Chris Liddell, chief financial officer. He added that Microsoft believed it was facing "the largest opportunity for innovation and growth the company has ever seen".