Strange gap between polls and betting markets

An interesting tweet this morning showing how the betting odds on the federal election have been fluctuating.

Probability of a Coalition win across betting houses 81.8% up 1.9pp on yesterday #ausvotes #auspol pic.twitter.com/2HIPfMqey6

— Mark the Graph (@Mark_Graph) June 15, 2016

I find the short price about the Coalition a bit strange. By my rough calculation it suggests that the market is guessing that the Turnbull team will end up with a two party vote share somewhere above the 53% mark. The opinion polls meanwhile have the current position near enough to 50:50.