Managing student lateness

What is the best way to handle students who come in to class late? I am not referring to the ones that do so occasionally and are contrite when they come in the room, more the ones that seem to do so regularly and almost ignore you when they walk to their desks.

Making a big scene in the lesson seems not so productive and could lead to general disruption. But ignoring will let a poor behaviour go unpunished. (if punish is even the right word?). As a new teacher in training this early part of the lesson can sometime disrail me as I am getting into a rythm.

Any advice appreciated?