Encouraging better student attendance?

Does anyone have strategies to support families who are less interested than other families in sending their children to school (Primary or Secondary)?

We have a few parents who say all the right things, but their children are still either very late to school or have poor attendance.

I'm not referring to families where the causes are known, more about families who seem to be very relaxed about attendance and punctuality.

What do you do to support them to improve attendance?