"When the worst of the weather passed at around 10 pm last night, we were able to send crews out to start restoring power to major feeders.
"With the weather now clear, we have had crews out at first light to begin clean-up and repairs to the network. However, the damage is severe and fallen trees are blocking roads, so it's going to take some time to work through it all. Customers should still be prepared for long periods without power."
Unison has brought extra crews into the region and has helicopters out to assess the full extent of the damage.
It is asking customers to listen to the radio for updates, follow its Facebook page and visit the website for updates: http://www.unison.co.nz/outages as call volumes into its call centre are significant.
Mr Gough said Unison's biggest concern was safety with some power lines down and reminded customers to remain vigilant, to always treat lines as live, and to be prepared that the power can come on unexpectedly, so should be treated with caution.
"When there is this much damage, our priority is to ensure that CBDs, businesses and industrial customers are connected first, then residential customers and those in rural areas.
"We are really grateful for all the understanding our customers are showing and just want to assure everyone we are doing all we can to get people back on as soon as possible. While Cyclone Cook was short-lived, it was also very destructive as we were warned, and Hawke's Bay has certainly felt its wrath."
Meanwhile Spark said in a statement this morning that while the Spark mobile and broadband networks were running as usual in most of the country, the Bay of Plenty, East Coast and Hawkes Bay areas had borne much of the brunt of Cyclone Cook overnight and there were power related telecommunications impacts in those areas.
"As of this 9.00am morning in those areas there are 12 cell-sites down and another 16 cell sites and 40 PSTN cabinets operating on battery backups. Our teams are working hard alongside local power companies and Chorus to restore coverage to these sites, either by restoring mains power or prioritising the deployment of generators. Please note localised flooding and slips may make getting access to some of these sites challenging."
"To help people stay in touch during the effects of Cyclone Cook we have opened our Free WiFi network to anyone who needs to use it, nationwide. If Spark customers have to evacuate their home as a result of Cyclone Cook, we can arrange to have their landline redirected to their mobile - just private message Spark via social media with their number and include #cook and we'll prioritise them.
