Motorists travelling between Picton and Christchurch this weekend - are being told to prepare for extra traffic

NZTA says there'll be extra vehicles on State Highway One, with people travelling to Kaikoura for the annual Hop car enthusiasts' event.

Traffic will be down to one lane at some sites, where the highway rebuild and repair is underway.

There'll also be extra traffic heading to Dunedin, for Saturday's Fleetwood Mac concert.

And from next Tuesday, the Hapuku Bridge just north of Kaikoura will be closed from 2 until 4am every Tuesday - for bridge pile repairs.