Sony Ericsson has moved to quell rumours that it is about to launch a mobile device that combines gaming and phone functionalities.

The electronics giant fuelled speculation that it was preparing to add mobile phone technology to a next-generation PlayStation Portable (PSP) with a recently filed patent application in the US detailing a "mobile device with gaming functionality".

Sony told Reuters that it is not poised to launch a phone based on the PSP, but did not rule out the possibility of such a device in the future.

"We are continually evaluating other propositions but they have to be credible," said Sony Ericsson spokeswoman Merran Wrigley.

"We are not interested in sticking parts on phones that destroy the brand equity that has been built up by Sony."

There has been no word from Sony's gaming division about a new PSP, much less one with a phone built in, Reuters added.