Witnesses posted pictures of a large, black plume of smoke above the area, which could reportedly be seen for miles.
Kent Fire and Rescue tweeted "a large quantity of rubbish" was alight on the estate. Residents have  been urged to close their windows and doors.
The fire service said the blaze was being brought under control.
Chris Skinner, 54, lives opposite the estate and told BBC News he first noticed the blaze around 18:15 BST.
Mr Skinner said the fire raged for a couple of hours, but had started to die down by sunset.
Another eyewitness, 24-year-old Rhys Mortley, said he could see the blaze from a golf course three miles away.
He said friends had reported seeing the fire from Essex, across the Thames.
Kent Fire and Rescue said eight fire engines and specialist vehicles were dealing with the blaze.
A large fire has broken out at the Clipper Close Medway City Estate in Rochester, Kent.