The eagerly anticipated Z1010 had been expected to go on sale this month, but the official line from the phone maker is that the launch will take place sometime in the first three months of 2004.
Sony Ericsson has denied that the Z1010's launch date has slipped.
"It was always our intention to launch the phone in the first quarter of 2004," a company spokesman told ZDNet UK this week.
However, back in September 2003, Philip Rambech -- Sony Ericsson's UK and Ireland managing director -- told journalists in London that the Z1010 should hit the shops in January 2004.
"It will ship in the first few weeks of 2004 -- it's in the final stages of interoperability testing now," said Rambech, at an event to launch three new mobile phones.
The launch of the Z1010 could give a significant lift to the struggling 3G market, as the phone will offer a greater range of features than many existing third-generation handsets.
It has two displays -- a main screen plus a smaller one on the outside of the handset -- and two cameras. As well as video-conferencing, it will support MMS, email, Sony's memory stick format and Bluetooth wireless networking.
Sony Ericsson won't disclose which mobile phone operators might sell the Z1010 to customers, although it's been rumoured that Hutchison -- the only 3G operator running a commercial network in Britain at present -- is interested.