Continuity mistake: When the Nazis board the Bantu Wind, there are some shots of the pipe Indy is hiding in. During these shots, there's a big grey pipe right behind Indy's pipe. However, in the rest of the Bantu Wind shots, this grey pipe is on the left of Indy's pipe, not directly behind it. (01:36:19 - 01:37:05)
Visible crew/equipment: When Indiana frees Marion, locked in the cabin pilot of the Nazi plane just after one of the soldiers is killed by the blades, a set light is reflected on the plane's glass. (01:20:32)
Continuity mistake: As the truck pulls up next to the Command Tent, four soldiers lift the Ark's box and a fifth soldier, positioned between the two wooden posts of the Ark's box and to Gobler's right, picks up the sticks that Indy and Sallah had used. In the next shot, that soldier is now to the left of Gobler and the Ark's box. (01:21:40)
Continuity mistake: After Toht's command, the Mongolian and the Nepalese grab Marion, then the former puts his hand on Marion's cheek. During this, the Nepalese faces Marion, whose mouth is open. In the next shot, the Nepalese is suddenly looking at Toht, Marion's mouth is suddenly closed, and the position of the Mongolian's head has changed. (00:30:28)
Continuity mistake: On the Bantu Wind, after Dietrich takes Marion from Katanga and begins to leave, the soldier next to the pipe where Indy hides throws his cigarette and leaves the scene. In the next shot, when Belloq stops Dietrich, the soldier is now back at his original position. (01:36:51)
Continuity mistake: In Geheimhaven, Indy watches the submarine hidden behind some ropes. When Marion comes out of the submarine and the camera focuses on the back of Indy's head, the ropes disappear. (01:39:13)
Answer: The scene you describe was indeed filmed. It was cut out of the US release of the film although I cannot speak for the Australian version. The scene also appears in the Marvel Comics adaptation. http://www.theraider.net/films/raiders/deleted_scenes.php has a list of this and the other deleted scenes.
Phil C.