Hi.
The next convention in 2018 is scheduled for Nelson in the South Island.
Then the 2020 convention is in Hamilton in the North Island.
Check out the MEANZ website
http://www.pnmec.org.nz/meanz.php and the clubs websites for further information
http://www.hme.co.nz/ and
http://www.nelsonmodellers.org.nz/