Infinitive without “to”

This is the use of "need" as an auxiliary, like "ought" or "must". Auxiliaries are followed by the plain form of the verb without "to".

...except for "ought". Other auxiliaries are "can", "will", "should", "would", "might".

we call them modal verbs.

"He needs not wait" does not seem right to me. I would say, "He does not need to wait."

Is it ok to say HE NEED NOT WAI(T as the word, need, serves as an auxiliary??

An infinitive without "to", also known as the bare infinitive, is used after modal auxiliary verbs (amongst others), for example:

"can do, will do, must do" etc

The verb "need" is a semi-modal, which means it can be used like a modal auxiliary verb or an ordinary verb:

"He need not wait." - modal with bare infinitive
"He doesn't need to wait." - normal verb with "to"-infinitive

The modal use "need" really only occurs in negatives an questions "Need I do it right now?", and normal verb use is probably becoming more common, and the modal use .

As far as I'm concerned "He needs not wait."is ungrammatical: it is neither modal nor normal verb use, but is trying to mix the two. At Oxford Online they say "he need not worry, not he needs not worry":

http://www.oxforddictionaries.com/definition/english/need (see Usage Note)