The lower North Island has joined the South in the shift to digital television, leaving viewers still using analogue sets unable to watch TV.
The area from Wellington to Gisborne and Taranaki went digital early this morning after the analogue signal was switched off.
Information from Going Digital showed 18,110 homes in that area were still using the analogue signal a month ago.
Most people were prepared for the change in time, Going Digital's national manager Greg Harford said.
"Don't forget if you haven't yet gone digital, or if you have other TVs that are no longer receiving pictures, you can go digital at anytime.
"People with old analogue sets can make them go digital with a set-top-box. If you want to dispose of an old TV, it's a good idea to recycle it responsibly,'' he said.
According to Consumer New Zealand's guide to Going Digital, the cost of a standard set-top terrestrial box set would cost between $80 and $200.
A set-top satellite box set would cost between $80 and $180.
But sickness beneficiaries, pensioners and community card holders over age 75 might be able to receive help with set-up costs, Mr Harford said.
Hawke's Bay and the South Island have already gone digital and the upper North Island will go digital on December 1 this year, at which point the whole country will be covered.
"This will free up radio spectrum for new services such as 4G mobile phones, which are expected to be cheaper and faster in the long run,'' Mr Harford said.
A digital signal could carry more information than the old analogue network, which was the way viewers had received television signals since television began.
The digital service is expected to deliver better picture and sound quality, and let broadcasters offer more channels and services like on-screen TV guides.
To keep watching television, viewers must have Freeview, Sky or Igloo.