A 79-year-old man can be prosecuted for allegedly raping his wife almost 50 years ago even though it wasn't a crime in 1963.

The South Australian Court of Criminal Appeal has paved the way for the man to be tried after a two-to-one judgment published this week.

The case had been referred to the appeals court from the District Court, which asked for a decision on whether the rape of a spouse was an offence in SA in 1963.

Chief Justice John Doyle said statements by judges and writers of textbooks in 1963 would have suggested that under common law a husband could not be found guilty of raping his wife, except in exceptional circumstances.

"Since then, it has been clear that it is no longer the law that a husband cannot be guilty of raping his wife," he wrote in his reasons.