As an Australian, I'm accustomed to pronouncing it na-YOE-mee. Pretty much everyone else I know pronounces it that way.
But in Japanese, there is an even amount of stress on all syllables. There is no exaggerated amounts of stress on all of the syllables, resulting in na-yo-mi. There is no 'YOE' sound at all.
If this doesn't make any sense, I explained it here: http://www.behindthename.com/bb/arcview.php?id=591797&board=gen
Hope this helps!