Up front, Emblen can run a first-choice All Whites strike-force with Smeltz, Chris Wood, Kosta Barbarouses and Marco Rojas and Nelsen and Tommy Smith are also automatic choices in Ricki Herbert's starting XI.
Adam Thomas (Waikato FC), Alex Feneridis (Auckland City), James Musa (Team Wellington) and Dakota Lucas (Team Wellington) are the only players other than O'Keefe who haven't appeared for the All Whites but Thomas, Musa and Lucas went to last year's Under-20 World Cup in Colombia and Feneridis has been to two Club World Cups.
Strikers Greg Draper and Sean Lovemore and midfielder Cameron Lindsay are notable omissions but, with so many internationals to choose from, there was plenty of competition for spots.
The Oly Whites have hopes of advancing from their group and are targeting their first two games against Belarus in Coventry on July 28 (NZT) and Egypt at Old Trafford on July 30 (NZT). They round out their campaign against Brazil at Newcastle's St James' Park on August 2 (NZT).
They need to finish in the top two in their group to advance to the quarter-finals and probably need at least a win and a draw to advance.
New Zealand Olympic football squad: Jake Gleeson, Tim Payne, Ian Hogg, Tim Myers, Tommy Smith, Ryan Nelsen (c), Kosta Barbarouses, Michael McGlinchey, Shane Smeltz, Chris Wood, Marco Rojas, Adam Thomas, Alex Feneridis, James Musa, Cameron Howieson, Dakota Lucas, Adam McGeorge, Michael O'Keefe.