Heavy fog has made for tricky conditions on Auckland's motorway network with crashes and breakdowns causing headaches for commuters.

Crashes on both north and south bound directions on the Southwestern Motorway (State Highway 20) have been causing heavy delays.

A multi-vehicle crash near the Dominion Rd on-ramp had been blocking the right southbound lane but had since been cleared. There was congestion from Waterview Tunnel to Dominion Rd.

Fogbound: Flights cancelled, multi-car motorway crash


Meanwhile on the other side of the same stretch of motorway a crash between Neilson St and Queenstown Rd blocked the right lane.

By 8.55am it had been cleared but delays from Manukau to Onehunga were expected.

On the Northwestern Motorway (SH16) a breakdown had been blocking the left lane prior to the Royal Rd overbridge, causing delays through Westgate, but had since been cleared.

Another breakdown on SH1, the Southern Motorway, southbound after the Symonds St on-ramp was also causing some delays.