Traffic cameras could become more common - as NZTA takes over responsibility from Police

It will increase the 150 cameras to 200 -- but is looking to have up to 800 operating within 10 years, manned by as many as 400 staff.

It estimates they could process three million speeding infringements a year.

NZTA's, Tara McMillan, says that figure's an upper limit.

She says at current levels it wouldn't be hitting that high, and their end goal is no infringements at all.