Initially a media report said all flu shots were free. According to reports yesterday and this morning that isn't quite so.
There is a current report that flu shots are free for those who are under 18 and over 65. This is according to news websites Scoop (here) and TVNZ (here), quoting an interview with the Canterbury Medical Officer of Health, Dr Ramon Pink.
Neither the Canterbury District Health Board nor the Pegasus Health websites mention flu shots at all.