All television viewers will be required to have a satellite or Freeview receiver when the Government switches off analogue signals in 2013.
Prime Minister John Key said in June that no decision had been made, but his instinct was that it would be in 2015.
However, the Government is expected to announce that from 2013 every home will need to go digital, a source has told the Herald.
That means that from 2013 they will need a digital decoder or Freeview tuner in TV sets to watch free-to-air channels - including TV One, TV2, TV3, C4 and Prime.
Around 65 per cent of New Zealand homes have Sky- or Freeview-enabled sets.
But politicians have been wary about switching off the old signals in case it brings a political backlash from people forced to buy new technology.
The TV networks have been broadcasting in both analogue and Freeview since the latter started in May 2008 - costing them extra.
In March, Sky closed its analogue channels and moved subscribers to digital.
Vodafone and Telecom are keen to buy the old analogue television channels to deliver mobile and other wireless broadband.
The Government would earn millions of dollars from auctioning off radio frequencies - what is called "the digital dividend".