Can anyone help identify this lizard?

Hi guys,

This is the resident skink family living under the front deck of our place just north of Cairns, Australia. wondering if anyone out there might know what they are.
They look just like the common garden skink although they are much much larger. the mature lizard in these pictures would stretch out to 40cm. They are like a blue tongue except the stripes go the wrong way! are they native?
can anyone recommend a good reference for identifying north australian lizards?

I usually have my camera out in the garden for photographing birds, which i am much better at identifying!! Check out my other posts to meet some wildlife that lives with us in the rain forest just north of Cairns, Australia. Ive been introducing 1 bird species at a time, and now a lizard!

Please resteem and forward this on so we can find out what type of lizards my friends are!