Connections could slow if users don't pay up. Christopher Furlong / Getty Images WASHINGTON (Reuters) - Verizon Communication Inc's high speed wireless customers who subscribe to the company's legacy unlimited data plans might experience slower speeds starting Oct. 1, the company said on Friday.

The announcement comes as wireless carriers attempt to shift data-hungry subscribers onto tiered plans, which charge customers for individual data packages.

Verizon will slow services for the top 5 percent of data users who are on unlimited plans in places where the network is experiencing high demand, the company announced on its website.

The policy will affect customers who consume more than 4.7 gigabytes in a single billing period who are on unlimited plans and who have fulfilled their minimum contract terms and are subscribing to service on a month-to-month basis.

Users might experience slower speeds when streaming high-definition video or during real-time online gaming, the company said.

Customers on the company's tiered data plans will not be affected.

The policy is currently in effect for unlimited subscribers on the 3G network, but will be expanded to its 4G, higher speed network in October.

Verizon stopped offering unlimited data plans in 2012.

(Reporting by Marina Lopes. Editing by Andre Grenon)