Damaging gusts and severe downpours are gathering steam, with Cyclone Vaianu set to hit.

Watches and warnings cover the upper half of the country, and a scattering of regions between Northland and Hawke's Bay have declared States of Emergency. 

Heavy overnight gusts have already knocked out power for thousands of homes, with crews out this morning working to restore supply. 

Whitianga could be cut off at High Tide - with the deluge causing flooding in the Coromandel. 

Several Auckland Roads are also seeing flooding - and NZTA warns there could be more road closures across Waikato and Bay of Plenty. 

MetService meteorologist John Law says strong Northeasterlies at the eastern flank of that low pressure system, are driving the large seas and strong winds around the Bay of Plenty. 

LISTEN ABOVE

• Hawke's Bay coastal communities brace for 1pm high tide as winds pick up
• What drivers need to know as Northland highways face slips and flooding
• Cyclone Vaianu cuts off Whangārei coastal communities again after heavy rain
• 'We've come off lucky': Northland largely spared as Cyclone Vaianu passes
• Watch: 'A bit more intensification to come' - cyclone's peak to coincide with high tide
• Live: State of emergency warnings spread - Northland, Waikato, Hawke's Bay, Whakatāne, Western Bay of Plenty
• Cyclone warning: Hastings mayor tells coastal residents to consider evacuating