Sony's next-generation console sells for $599 (£305) in the US, and ¥60,000 (£252) in Japan. Even in Ireland, PlayStation 3s will be selling for less than the equivalent English price.
"We do not buy anything in dollars, and the dollar can go up and down," Ray Maguire told The Guardian.
"If it were $1.40 to the pound as it was in 2001, the PS3 would be a bargain compared to the US, but if it's anything more than that the UK price appears to be comparatively expensive.
"But we are dealing with euros and yen, and it's about the relationship between those currencies."
Maguire also blamed the high cost of living in the UK, where Sony has to pay its staff more than in Japan and the US, and the fact that retailers take a bigger cut of the profits.
The £425 price tag is for the PS3 with a 60GB hard drive. A cheaper model with a 20GB hard drive and no Wi-Fi will not be available in the UK on launch. Maguire claimed that this was down to consumer choice.
"A big preference has been shown towards the 60GB model. And when we look at the sales figures from Japan and the US, that is reflected at retail," he said.
"You can either have not enough of both [versions] in the marketplace for day one, or you can have round about the right amount of one."
Around 220,000 PS3s will be made available to the UK on its launch on 23 March. Retailers are already reporting that demand will outstrip that figure significantly.
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