All lanes on a major motorway in Wellington have been opened but motorists have been told to expect "extensive" delays.
A northbound and southbound lane on State Highway 2 were closed after two crashes near Horokiwi, west of Lower Hutt, early on Thursday morning.
A northbound car smashed into a power pole leaving one person seriously injured.
A short time later a southbound diesel tanker and fruit truck collided, spilling diesel over the road.
The Upper Hutt and Melling train lines were shut down for more than two hours as a precaution because the diesel had spilt near the tracks. All lines have since reopened but delays were expected.
A New Zealand Transport Agency spokesman told NZ Newswire all SH2 lanes have been opened although motorists can expect "extensive" delays and the motorway remains congested.
Alternative routes through SH58 and SH1 are also congested.