What wording should i use in expressing qualified audit opinion when there is insufficient audit evidence? -

It would be difficult for someone to answer that without knowing the context. I write audit reports all the time, but it would be difficult to offer an appropriate suggestion based on what you've listed here. "These findings are preliminary due to limited testing and fieldwork performed" or "These findings are qualified due ... etc...." - these are just 2 examples - really depends on the facts