The rollout of the National Broadband Network is ramping up in the Illawarra with thousands of residents in Dapto, Marshall Mount, Penrose, Coniston and Mount Saint Thomas now able to connect to the NBN.

Telstra has started offering the next generation in high-speed telecommunications to almost 4000 new homes and companies in Wollongong.

NBN on high-speed fibre technology first arrived in Wollongong, including Dapto and Corrimal, in January; now more than 20,000 premises are now eligible to connect.

Telstra Country Wide Illawarra area general manager Tricia Wilson said a range of new services and applications were now within reach of residents and businesses.

"Illawarra is already a thriving home for families and the arrival of fast broadband will make it an even more desirable place to live," she said.

Ms Wilson said that with web use in the home on the rise, the NBN would provide the bandwidth to get families all online at the same time.

"Fast broadband also opens up some terrific possibilities like attending a specialist appointment from home using video chat, or for students to participate in lectures online when they can't be at university," she said.

"We're seeing phenomenal interest in streaming video services as a way to enjoy TV shows and movies independent of broadcast schedules."

Ms Wilson said the NBN was also good for businesses, handling large volumes of data quickly and supporting technologies like online sales, cloud computing and video collaboration.

Telstra is also introducing Telstra Air, which allows customers to use their home broadband allowance at Wi-Fi hotspots across the country.

Meantime, more than 2200 homes and companies in Dapto and Brownsville were disconnected from the copper network from August 14.

Other areas of Dapto, Kanahooka and Koonawarra will be disconnected by February.

NBN spokeswoman Kelly Stevens said it was vital that people understand that the switch was not automatic and that they needed to place an order for NBN.

If residents do not move their landline phone and internet services over, they would not be able to use them once the copper network was "switched off".

Information: nbnco.com.au/maps