Flag of Flevoland, Province of the Netherlands. (gif linked from flagspot.net)
Flag of Sierra Leone (gif linked from www.flagspot.net)
Note the flag has equal-sized bands and no distinguishing pattern such as a koru. The green in the coat of arms is symbolic of the hilly mountains, white and blue are for waves (i.e. sea). Smith (in www.flagspot.net) adds that the white in the flag stands for unity and justice (cf. the national motto). Smith also calls the shades of the colours "leaf green" and "cobalt blue".
The flag of Gabon is similar, again a tricolour with equal-sized Green (above) Yellow (above) Blue bands.
Flag of Uzbekistan (gif linked from www.flagspot.net)
The Blue, White and Green are in the same order as on my flag and there is a moon and stars motif. However the colours are lighter and are separated by red lines. The white band is wide and rectangular.
An interesting coincidence: Genovia
The movie "Princess Diaries 2" is set in the fictitious but beautiful country of Genovia, somewhere between France and Spain. It has a green white and blue flag with the Genovian coat of arms on the white band. This looks quite attractive.
All told, then, there would be no flags that could be confused with my proposed New Zealand one, especially with the koru on the end.