I dont know if the Hokianga is the same, but on the inside of a bar there is often an area where pressure waves build up rather mean... even on a flat bar, an area where one could get into trouble in a kayak .
Have you been over in a boat to check it out?
bars are very different out there to from the shore
Kayak experienced in river white water?
Or surf?
Going alone or have escort?
And keep in you could have 1 to 2km from one side to the other...
You you have an understanding between swell period and swell height and how that effects the larger sets of waves?
ie you may have say a 1m swell, but if have say a 20/24m period, those small sets will be nothing, the big set come in and those waves will stand up 2m+ as the period on the bar compresses..
Throw in the distance, you could very well have to go thru at least one large set.. also n the sets have sets, around the 21 and bigger 42 nd are where those so called 'freak waves ' are.
plus having all the usual epirp/ safety equipment of coarse...