[susan53]

You have two choices here : you can see it as 1) describing the past, or 2) describing a time before a stated present point

If you see it as describing the past, you would say:

This is my first trip. I was never here before.

This means I was never here at any time in the past.


However, you can also see the meaning as "never before this visit" and "this visit" is present.

I've said in other answers that have/had + past participle (perfect verb forms) can be used to show the sequence of events. The event in the perfect form is understood as happening before another stated (or understood) point in time. For example :

When you have fried the tomatoes, add the salt - frying the tomatoes happens first, adding the salt happens second.

The plane had left when I got to the airport - this tells me that the plane's departure happened first, and my arrival happened second. Notice that here the verb is in the past perfect (had +pp) because both events are in the past.

So in your example, you can interpret "before" as meaning "before this visit" - ie before the present. So :
I've never been here before (this visit) - never visiting Australia happens before the reference point - the visit - which happens second. The verb is in the present perfect (have+pp) because the reference point (=the visit) is in the present.

This is a difficult use of the present perfect to understand. Textbooks often explain it by saying that if it's a past event but the exact time isn't stated, then use the present perfect. This isn't completely correct, but it is an easy way to remember it.

However, if you find it easier to see the event as past, just say I was never here before - it's fine.