UPDATE - 2.30pm:
Both lanes are now open.
1.36pm: Police are advising motorists to expect delays following a two vehicle crash at the bottom of the Brynderwyn Hills.
A car and van collided with each other at about 1pm today, blocking the northbound lane of SH 1, 200m north of the Atlas Quarries.
Police said motorists traveling north should expect delays and traffic will be diverted down SH 12 while the road is cleared. The lane is expected to be blocked for about 30 minutes.
It is not clear how many patients are involved but police said at least one patient has received moderate injuries.