McCullum said the decision was not made lightly.
"I have talked to a lot of people about how they went about extending their international careers, including some prominent former and current wicketkeepers," he said.
"I'm passionate about playing for the Black Caps and by limiting my keeping to the shorter forms of the game it increases my chances of prolonging my career."
New Zealand Cricket's general manager of cricket, Geoff Allott, said the news was good in the long term.
"Brendon enjoys the challenge of test cricket and has been a strong performer for New Zealand as keeper over a significant period of time," Allott said in a statement today.
"While his glove work will be missed, we understand and support his decision to focus his attention on scoring runs at test level, and his objective to play on the international cricket stage for as long as possible."
Allott said NZC was keen to work with players such as McCullum, ensuring they stayed fit and available for selection, with particular attention being paid to those with heavy playing schedules.
Black Caps coach Mark Greatbatch said the selection panel also understood McCullum's decision.
"Brendon has stated he wants to play cricket for New Zealand for as long as possible and that is really encouraging."
Greatbatch said McCullum had been troubled with injuries related to keeping, and his decision to stop keeping in test cricket was understandable.
"He's a really talented player and we want him to be part of the Black Caps' set-up for a long time to come."
McCullum understood he would only be considered as a test batsman on his long-form batting performances, Greatbatch added.
