Cheers for the reply's so far
I'll try and explain what I experienced:
Started the night off at Wai-iti, not much happening there so packed up and left at 22:30
On the way back to NP I stopped in at the local for a lazy hour to finish off. It started off slow then a couple of spikeys were caught and realeast then I had a real good take but dropped, this happened another 2 times before I hooked and landed a nice lemon. while this was all taking place I was starting to get some strange takes, nibbles, pulls and bites.
Watching the rod tip it would tap like something was playing with it then you'd get a sure bite or 3, i'd pick it up let it have another go give it a wack and start winding in a weight with no real fight once I got it to just behind the beach break (wave) it dropped off.
Some notes:
Rod tips were all over the place- pulls, bites wobbles, nods, shakes, when in hand some of the pulls were a good half a metre.
If I struck too hard, nothing, sometimes it would bring my line in on me but not that often.
I tried bringing it in slowly got close but no, changed hook sizes etc.
At the start I thought eels but they're not this good. This lasted 1.5 - 2 hours and was consistent (i.e. every bait) I tried allsorts to try and land whatever it was and I ended up rather frustrated.

Species that popped into my head
Eels - None caught that night and there normally easy to catch
Crabs - ?? if they were they felt a good size
Trev's - these buggers are this cunning/tricky been that long since catching them I can't remember what they're like??
Sharks - I was catching Spikeys through the night with the one good lemon so I don't think so I knew when I had a shark playing with me I think
Crayfish??

I have no idea what it was but would love to here your thoughts?