A Kiwi caught in the devastating Hurricane Irma is poised to head into a makeshift bunker as dangerous winds pound her Florida home.

Sue Hamer says she is "hanging in" while the powerful category two storm tracks across the southern state leaving a trail of destruction in its wake.

So far three people have been killed in weather-related road accidents in Florida. The powerful storm earlier claimed the lives of 25 people when it roared through the Caribbean islands.

Hamer said she was taking cover in her home ready to tuck into wine, chips and dip as the eye of the storm passed over Naples, just an hour from her city.

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She said violent winds were howling outside her home, slamming into the steel window shutters.

Power had been intermittent throughout the day and everyone was feeling anxious but trying to keep spirits up.

"We are hanging in there. The eye is about one hour away and we will head into our 'bunker' soon.

"It's well stocked with wine, Kiwi dip and chips," said Hamer.

Another Kiwi, Caryn Haynes, sheltering with friends in Fort Lauderdale, said there had been 12 hours of horrendous weather.

"We're not doing too good," she said.

"We've been sitting in the rain band of this storm for 12 hours now and we're just waiting for it to move north."

Haynes said backyards in her neighbourhood had been swamped by an adjacent canal while the front road was inundated by flooding.

"Our street front is a river."

The destructive winds had toppled trees and cables had come down across roads.

She said she was riding out the storm with neighbours playing cards and looking after her pet golden retriever, Kiwi, who was very relaxed despite the carnage unfolding outdoors.

Another New Zealander in Florida, Anna Wilding, described the situation as diabolical with her home pelted by coconuts raining down on the roof like cannonballs.

"It's really bad," said Wilding from her Palm Beach home. "It's too dangerous to open a door outside."

The area was in blackout with treacherous conditions expected to continue for hours.

The region faced an ongoing threat of tornadoes as extremely high winds, thunder, lightning and rain continued.

Florida remains in the grip of the monster hurricane with winds over 200km/h slamming into the sunshine state.

Streets have been submerged by rising floodwaters, construction cranes have snapped like twigs across the Miami skyline and power has been knocked out to millions.

The 640km-wide storm blew ashore Sunday morning (local time) hitting the Florida Keys and tracking up the west coast of the peninsula.

State leaders have asked people to pray for everyone in Florida as tens of thousands seek shelter in stadiums.

Tornadoes have added to the misery, destroying mobile homes in Palm Bay, hundreds of kilometres away on the Atlantic coast.

Meteorologists expect the entire Florida peninsula will be raked by Irma's right front quadrant - the part of a hurricane that usually brings the strongest winds, storm surge, rain and tornadoes.

Curfews have been imposed in Miami, Tampa, Fort Lauderdale and much of the rest of South Florida, and there have already been arrests for looting.