Just like Steam. Steam/Origin can't take your account information out of nowhere without internet connection, but it's only one time action.
Just tested it specially for you: if I start Origin with no internet connection Login menu will have "Online login is currently unavailable" line asking me to enter my password. I enter my pass and it starts with no problem in Offline mode. I don't know what special version you are using but it's either not up to date or you are doing something wrong.