Smeltz returned from a hamstring strain for Glory against Adelaide United in the A-League on Sunday, coming from the bench to play about 20 minutes.
The 31-year-old then boarded a plane for Shanghai, where New Zealand will play China in a friendly in midweek.
Smeltz's injury restricted him to just one A-League game prior to Sunday and Perth coach Ian Ferguson hopes New Zealand realises the attacking linchpin is lacking match fitness.
Glory has discussed Smeltz's situation with the All Whites, coached by Wellington Phoenix mentor Ricki Herbert.
"The national team and our club have been in touch ... just to be a little bit mindful and respectful that he has not got any game time, so we don't want him to go and play the 90 minutes," Ferguson said.
"Maybe a spot on the bench would probably be a wee bit more realistic.
"At the end of the day, it's not a World Cup game, it's a friendly, so there shouldn't be any risks taking by Smeltzy - I hope not anyway."
New Zealand's next match in its 2014 FIFA World Cup qualification group is in March next year.
The All Whites are unbeaten in four Oceania zone matches against New Caledonia, Solomon Islands and Tahiti.
Should New Zealand log an expected group win, it will face an intercontinental play-off match against the fourth-placed team from the North, Central America and Caribbean zone, with the victor claiming a spot in the World Cup in Brazil.
New Zealand has made two World Cups, in 1982 and 2010 when, although not advancing past the group stage, it was the only nation not to lose a game, with three drawn matches.