Which half will start first on Monday?

I may be wrong but this is just my observation. Aus Open organisers want (and hope that) an Aussie male player will reach the 3rd round so that they can feature in the night match on Rod Laver Arena for the first Saturday night.

So whichever half of the draw that Aussie male player is in - (it was Hewitt in the past up until 2012, then it was Tomic in 2013, and last year - more Aussies were in the top half of the draw), then that half of the men's draw will start second.

Having looked at the draw for this year's Aus Open, all of the Aussie male players (with the exception of Lleyton Hewitt) are in the bottom half of the draw. I would take a punt and say that this year, the top half of the men's draw (Djokovic's half) will play first, along with the bottom half of the women's draw.

From 2005 onwards, this is how the order of play between the two halves of the draw has played out - and I'll include which half of the draw Hewitt was in (up until 2012), and then Tomic (in 2013)
2005 - Hewitt was in the bottom half/top half played first
2006 - Hewitt was in the top half/bottom half played first
2007 - Hewitt was in bottom half (lost in 3R to Gonzo - that was on the first Sat night on RLA)/top half played first
2008 - Hewitt was in top half (that infamous match vs Baghdatis that finished at 4:30am on the Sunday morning thanks to Fed vs Tipsarevic going 4.5 hours)/bottom half played first
2009 - Hewitt was in top half/bottom half played first
2010 - Hewitt was in top half/bottom half played first
2011 - Hewitt was in top half/bottom half played first
2012 - Hewitt was in top half/bottom half played first
2013 - Tomic was in bottom half/top half played first (Tomic played Federer in 3rd round, Hewitt was drawn against #8 seed Tipsarevic 1st round - organisers def knew who would get through there)
2014 - Hewitt/Tomic both in top half/bottom half played first
2015 - All Aussies except Hewitt in bottom half/top half will play first???