City spokeswoman Colleen Roberts told ABC News that volunteers are using private boats to pitch in and help.
"You may need to move up to the second story, or to your attic, but WE ARE COMING TO GET YOU," the city said in a tweet.
The flooding started Thursday night and continued into Friday.
As the hours passed, the floodwaters continued to rise.
VIDEO: Hurricane Florence as daylight breaks in New Bern
VIDEO: Hurricane Florence as daylight breaks in New Bern
By Thursday night, the city had already experienced heavy flooding, with waist-deep and shoulder-deep waters.
Watch: Cars trapped, buildings inundated with substantial flooding in New Bern
New Bern Florence video: Cars trapped, buildings inundated with substantial flooding
Many streets are flooded and heavy winds have knocked down fences and trees.
Florence made landfall just before 7:30 Friday morning as a Category 1 storm.
It's estimated that the storm will dump 1 trillion gallons of water -- that's enough to take 581.4 billion showers.