More than half a million people may have been ordered to evacuate Florida as Hurricane Irma nears, but one county sheriff will leave sex offenders and people with warrants to weather the storm.

Key points: A Florida county will not allow registered sex offenders access to shelter

A Florida county will not allow registered sex offenders access to shelter Police will check IDs at every shelter and will arrest anyone with a warrant

Police will check IDs at every shelter and will arrest anyone with a warrant Effects of Hurricane Irma are expected to hit the county on Saturday

The category-five hurricane is dubbed one of the most powerful Atlantic storms in a century, and has already devastated a string of Caribbean islands, killing at least 14 people.

Irma is expected to make landfall in southern Florida on Sunday, bringing devastating 290kph winds, before it eases back to a category-four.

Florida Governor Rick Scott has called for mandatory evacuations from the life-threatening storm.

But Polk County Sheriff Grady Judd tweeted on Wednesday he would not open shelters for everyone.

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He also tweeted that anyone with active warrants would be taken to the "safe and secure shelter called the Polk County Jail".

The sheriff did not mention any alternative shelter for registered sex offenders.

"We cannot and we will not have innocent children in a shelter with sexual offenders & predators. Period."

The statement received mixed responses.

Twitter user Jennifer Hayden tweeted: "But you are perfectly willing to force people to risk their lives because they have a warrant for parking tickets? Way to protect and serve."

Patricia Mullis tweeted: "Pretty sure Jesus wouldn't have done that, Grady."

Polk County spokeswoman Carrie Horstman said it would not be possible for officers to see details of the warrant, making it possible for people with non-violent misdemeanour offences to be taken into custody.

The county will open shelters on Saturday, based on projections on when Irma's effects might be felt.