The Wellington Phoenix have lost electronics giant Sony as their major sponsor.

Sony New Zealand has been the main sponsor since the club's inception in 2007 but will reduce its involvement in A-League football to focus on next year's World Cup in Brazil.

A Phoenix release said it was a "key strategic step" by Sony to "widen the scope" of its strong relationship with the world's most popular sport.

Phoenix general manager David Dome described Sony's decision as bittersweet.

"We have enjoyed a strong partnership with Sony as they have been our major sponsor since the club's inception," he said.

"Without Sony, the Phoenix would have struggled to get off the ground in 2007, and for this the club is truly thankful.

"We are delighted to have been part of the growth of Sony's association with football globally.

"Both parties are keen to have an ongoing relationship at a lower level, but this decision needs to be in the context of the new principal partner."

Sony NZ country manager Martin McManus said the company was honoured to have been heavily involved with the Phoenix.

"Although Sony will no longer be principal partner, we will continue to be involved in promoting football in New Zealand as we begin the buildup to the 2014 Fifa World Cup in Brazil," he said.