ABC managing director Michelle Guthrie is facing conflict on a new front after two Labor MPs demanded the national broadcaster reverse a decision over the future of broadcasting in the Northern Territory.

Senator Malarndirri McCarthy and member for Lingiari Warren Snowdon have expressed "deep disappointment" and concern about the plan to end shortwave broadcasting in the NT from the end of January.

"Your decision to cease this shortwave service has caused consternation and alarm across the Northern Territory, particularly as it was not foreseen and had not been the subject of any discussion or consultation of any kind," Senator McCarthy and Mr Snowdon wrote in a letter on Monday.

"Subsequent to the announcement no reasonable explanation has been forthcoming. This has led to the conclusion by some that the ABC as the national public broadcaster has lost sight of its responsibility to provide services that are accessible regardless of where people live or who they are."