Green’s Dictionary of Slang

cob n.6

[abbr. cobber n.2 (1)]

(N.Z.) a friend, a mate.

[NZ]Street Society Christchurch 20 : [At a Christchurch youth club] Oh, a great party. You had somewhere to have it? Yeah, at a cob’s place [DNZE].
[NZ]G. Slatter Gun in My Hand 45: Too proud to drink with ya old cobs? A man oughta dong ya.
[NZ]R.M. Muir Word for Word 254: You weren’t actually married, of course. Not me, cob. She was keen enough, though.
G. Slatter On the Ball 140: ‘Righto, Spandau, me old cob,’ I say.
[Aus](con. 1945–6) P. Doyle Devil’s Jump (2008) 121: ‘Thin about it,’ he said. ‘I certainly will, old cob.’.
[NZ]McGill Reed Dict. of N.Z. Sl. 49: cobber A mate or friend, or sometimes merely the fellow alongside in manual labour. Cheery diminutives are cob and me old cob.