The 36-year-old - who last played for Borneo FC in Indonesia - earned 58 caps for the All Whites between 2003 and 2017 and nabbed 24 goals.
He scored the goal in New Zealand's famous 1-1 draw with Italy at the 2010 World Cup.
An old-fashioned predatory No 9, German-born, Gold Coast-raised Smeltz also played for clubs in Australia, England, Turkey and Malaysia.
He is second on the A-League's record goal scorers list with 92 goals.
He was the competition's top scorer in 2008-09 for Wellington and 2009-10 for Gold Coast United.
He also played for Perth Glory (28 goals in 58 appearance) and Sydney FC (12 goals in 43 games) in the A-League.
"It's difficult to put a career into words. The time comes to us all & I guess I know the right time is now for me to announce my retirement from professional football," Smeltz posted on Instagram.
"Now that I've closed the door on my playing days I'm looking forward to taking every bit of experience & knowledge I've gained into my next chapter and I'm pleased to say I will be staying in the game that I love until I stop breathing."
Smeltz said he'd now look to get into coaching.
