"We have crews regularly clearing rubbish from all parts of the highway network, and we respond quickly if we're informed of rubbish being dumped.
"The priority is on rubbish visible from the road."
He said because of the length of the state highway network and remoteness of some areas, it was not possible to completely prevent people determined to leave rubbish at the side of the road.
Though the transport agency can't prosecute for illegal rubbish dumping the local council or police can.
Hastings District Council investigates any rubbish dumped in the Hastings region and it is then dealt with under the Litter Act 1979.
Fines of up to $400 can be issued depending on the amount of rubbish.
Both local councils and the transport agency encourage people to report any rubbish seen to the appropriate organisation, because it is illegal, inconsiderate and harms the environment.
Rubbish along any state highway can be reported to NZTA on 0800 444 449.
Rubbish dumped in a reserve or along a beach can be reported to Hawke's Bay Regional Council.
People should call the pollution hotline on 0800 108 838 and note down the time, date and place along with a photo if possible.
Napier City Council and Hastings District Council are responsible for any rubbish in their local areas not in a reserve or beach.
Mr Oldfield said the responsibility for these acts lies squarely with the individuals dumping the rubbish.