But Emblen defended the decision and thought Smeltz was justified in focusing his attentions on solidifying his future in Sydney.
"Shane has had a stop-start season due to injury," Emblen said. "With him securing a deal at a new club, while we lose access to a top quality striker, I can understand the position he and the club are in ahead of a new campaign with a new coach."
Melbourne Victory attacker Barbarouses, meanwhile, is still recovering from the effects of a lingering ankle problem after a long season with his club which included their seven-match Asian Champions League campaign.
The withdrawals leaves the All Whites squad boasting a combined eight goals in international football but, looking on the bright side, Emblen said the door was now open for two young players looking to make an impression.
"Losing players from the squad at any time isn't ideal but that's the nature of football," the coach said. "What this situation does provide is an opportunity for Jason and James who are hungry young players excited by the chance to prove themselves in the All Whites environment."
The All Whites go into camp on Monday in Auckland ahead of Friday night's match.