Hi - Wondering if it is possible to activate a One NZ eSIM while in Australia?

Wife requested a port of her number from Spark NZ to One NZ onto a monthly plan.
Recieved an email to say it will happen tomorrow ~ 8am.

She flys out to Australia tomorrow and should be there ~ 9am.

Will she be able to activate the eSIM while there? And then we can enable roaming on her account?

Anyone done this before?

Thanks