There are many resources on the Web for researching Tango.
Here are a few
Auckland is only a 2.5 hour drive from Tauranga so you will often find dancers from the Bay of Plenty region at the Auckland Milongas and Workshops. For what's on in the Auckland Tango Scene go to http://www.aucklandtango.co.nz
New Zealand Tango Festival
3 days and four nights of world class workshops and milongas.
Summer Tango in Nelson
Summer Tango in Nelson, held on 10-12 March 2017, will bring together dancers from all over New Zealand and a few from Australia for the pleasure of social dancing.