The earmuffs can come off during television commercials after the networks decided to tone down the noise.

After years of viewer complaints about advertisements sounding much louder than normal programming, TVNZ, Maori Television and MediaWorks have all signed an agreement which will make them easier on the ear.

They reached an agreement on sound compression, a technique used in advertisements which makes the advertisements sound much harsher on the human ear, TVNZ reported.

The agreement is due to come into effect on January 1, but TVNZ says it will roll out the change from Sunday.

"We know how viewers feel, so why delay when we can improve their viewing experience and remove an obstacle to advertisers' success," TVNZ chief executive Kevin Kenrick said.

Sky TV has not signed up to the deal but has said it will comply.

Viewers surveyed in a 2008 Auckland University study believed advertisements sounded 50 per cent louder than normal programmes.

Association of New Zealand Advertisers chief executive Lindsay Mouat told the New Zealand Herald he was not perturbed by the change.

"It will reduce complaints about advertising, and that will be good for everybody. If people had to shout, you have to question if the ads were not very good."