"His effort and commitment in Fiji was first class and he enjoys scoring goals, as shown by him being the leading goal scorer in the New South Wales National Premier League this season.
"He hasn't been signed as a number one striker and will have to earn his place, but I have a good feeling about him."
Powell will arrive in Wellington later this month but he'll have to wait until October for his return to the A-League.
"Ernie Merrick has given me another chance at that level and it is up to me to repay him by scoring goals, which is something I love doing," Powell said.
"I got to know the Phoenix boys on the pre-season trip to Fiji and they are a great bunch."
The Phoenix kick off their A-League campaign on October 11 at home to Newcastle Jets.