UK mobile operators Vodafone and Orange appear to be selling the shiny new Nokia N95 minus the functionality to make VoIP calls.

Internet telephony firm Truphone has been making some noise about the fact its users cannot use their VoIP application on the device, while a number of new N95 owners have been complaining loudly in the forums about the lack of functionality.

Although the factory version of the device has a native SIP stack supporting close integration with internet telephony clients like Truphone, Vodafone and Orange have chosen to install their own version of the firmware minus the SIP stack.

It is reported that some free standing applications, which use their own SIP implementation still work.

Furthermore, some disappointed new owners of the device also complain that the Vodafone version of the N95 is missing the native Push To Talk (PTT) and instant messaging apps.

Intriguingly, an Orange spokesperson said the decision to remove VoIP functionality on the N95 was a “handset specific issue” and confirmed that VoIP is available on all other N series and E series devices and will be available on devices in the future.

“It is not Orange’s policy to remove VoIP functionality from devices. Orange was asked by Nokia whether they wanted the VoIP functionality switched on or off, and Orange selected off,” the spokesperson said.

telecoms.com is trying to find out what makes this phone so special in this regard. There has been no response from Vodafone as of yet but at the CeBit tech conference in March, Vodafone demonstrated calls being made using Skype. The company hinted that it may offer the software on its mobiles at some time in the future.

Using a menu bar that is strikingly similar to 3UK’s X-Series offering, Vodafone demonstrated the launch application for a combination of IP services including MSN Messenger, Skype and AOL IM. Vodafone calls the launch application ‘Starfish.’

Meanwhile, T-Mobile, O2 and 3 however, are understood to be offering the N95 as is, with the SIP stack installed. Or consumers could just pay the full whack and buy an unsubsidised SIM free gadget.

Alternatively, some users have taken their device into their nearest Nokia service centre and had it re-flashed with the factory firmware, restoring the original settings. The more adventurous users have re-flashed their phones at home although this will void the manufacturer’s warranty.

Be warned that re-flashing will also remove all other operator customisation.