Traffic is beginning to build on Auckland's highways as people head away for the long weekend.

State Highway 1 heading south and north is showing signs of congestion.

Updates on the New Zealand Transport Agency site show one area of heavy traffic has been identified on the highway heading north from Puhoi to Warkworth.

NZTA is advising motorists to consider using State Highway 16 from Silverdale to Wellsford instead.

Another area of heavy traffic is heading south after Manukau.