Domestic to intl connection Melbourne with diff airlines
 

Is 2 hours and 15 min. Enough to connect in Melbourne from Domestic to International? Dorm flight from Hobart is virgin. Intl flight from Melbourne is Qantas to Auckland? Bags cannot be checked through I'm told.
alternative is much earlier Qantas flight from Hobart.
thank you for your help in advance! This is due to an unexpected airline change.

You will definitely not be able to check your bags through.

According to Qantas website, the latest check-in time for international flights from major airport (e.g. SYD) if you are in Y/PE is 90 minutes, and J/F is 60 minutes.
https://www.qantas.com/au/en/travel-info/check-in.html

MEL international and domestic terminals are next to each other (including Virgin one which is T3 and next to the international terminal), thankfully, unlike SYD. You should therefore be able to get to the QF international check-in desk from VA domestic baggage carousel in 15 minutes.

However, add in the time it may take for your bag(s) to come out, and it is going to start to look a bit uncomfortable.
Personally, I not feel comfortable with the possibility of just a 30 minutes' delay causing me to miss the flight, on separate tickets (i.e. no protection for 'missed connection' because it is not a connection).

Have a think about it based on the information above, but I would definitely not do this myself, unless hand luggage only.

Also ask yourself what your risk tolerance is for skipping your QF flight if your inbound to MEL is delayed. You are not connecting because you are on separate tickets and QF will cancel your onward ticket if you miss the flight (this includes any onward or return segments). You would then be required to purchase a new ticket using whatever residual value your QF ticket might hold.

If you were connecting, the logistics would be your only concern. As you are not connecting, you also need to consider the financial risk.

Absolutely not enough time. Sure, it may be possible if everything runs to time, but the risk is quite big if on separate tickets. I’d start thinking about 3 hours minimum and preferably 4 hours. In fact, as BA Gold, that extra time can be spent in the QF MEL F lounge.

I would probably risk this in MEL, but... When exactly do you fly @Larkin? That might have impact... I am lazy to look for the flights, give us more details and (being HBA based) will try to give more insight...

Enjoy the F Mel lounge :-)