"Whether it's a joint venture or whether it's not, the Sony Ericsson component is a very integral part of the Sony strategy going forward," Hirai told the All Things Digital AsiaD conference in Hong Kong.
"The most import thing is that we are able to work a lot closer with the folks at Sony Ericsson."
The technology conference is sponsored by the Wall Street Journal, which published a report earlier this month saying Sony was nearing a deal to buy out the European telecom firm's stake in their mobile phone joint venture.
By wresting full control of the partnership, Sony aims to integrate its smartphone operation with its tablet, hand-held game console and personal computer businesses to save on costs and boost innovation, the report said.
Sony was said to be pushing for a deal as competitors such as Apple of the United States and Samsung Electronics of South Korea forge ahead with closely coupled strategies for smart phones and tablet computers.
The joint venture's two parent companies have held regular discussions over the years about Sony Ericsson's ownership structure, the Wall Street Journal quoted its sources as saying.
One of the sources said that talks were ongoing and could break apart at any time.
The amount Sony would pay Ericsson remained unclear because of the complexity of a possible transaction that could involve Ericsson's mobile-technology patent portfolio, the journal said.
Hirai on Friday dodged repeated questions about the report, which he described as "speculation". He added however that the two companies needed to work harder to create a "seamless experience for the consumer".
Sony Ericsson was created in 2001 and is now the world's sixth-largest cellphone manufacturer with a global workforce of 7,600.
Analysts have estimated that Ericsson's stake in the venture could be
valued at more than a billion dollars.