I'm flying from Auckland to Brisbane in Business class and I got a friend in economy, with Emirates, am I able to invite my guest into the Business class lounge?

I'm flying from Auckland to Brisbane in Business class and I got a friend in economy, with Emirates, am I able to invite my guest into the Business class lounge?

Only if you hold Gold status or above with EK or QF, and you both need to be on the same flight at least in the case of the Emirates lounge.

My understanding is that if you are flying in Business with EK, you have access to their Lounge, but to invite a guest may require you to have status (Gold). If you are a QF Status holder, you can bring your friend.