Bay of Plenty motorists have been warned not to travel if they do not need to due to concerns over bad weather and driver inattention.
Waikato police have asked drivers to keep off the roads if possible, to alleviate the region's gridlocked roading network.
District road policing manager Inspector Freda Grace said between 6am and 2pm today, emergency services have been kept busy attending and trying to clear several crashes.
Mrs Grace said a number of the crashes have involved commercial vehicles including one which closed the intersection of SH2 and SH25 at Mangatarata about 9am when a truck hit a barrier.
Read more: Severe thunderstorm watch for Bay
"Routes to popular holiday destinations in the Coromandel and Bay of Plenty are particularly affected as these are also routes transited by heavy transport vehicles servicing the ports of Tauranga and Auckland," she said.
"It's not just crashes making life difficult, as this incident was going on reports came in of two trucks breaking down on SH29, one on the Matamata side and one near the summit of the Kaimai Range.
"If that wasn't bad enough a car hit a fence in the wet about 9.30am on SH27 near Kaihere while another car crashed on the same road about 1.30pm.
Mrs Grace said the cause of the various crashes is yet to be determined but she feared drivers not adjusting to the conditions and inattention could have played a part.
"Speed and not driving to the conditions seems to be a common theme today."
Mrs Grace said with further bad weather forecast the Police's message is a simple one.
"If you don't need to go now, don't. Wait till it fines up and if you absolutely have to drive, make sure you drive to the conditions and as they've changed, so should your speed."