Australian veteran Peter OMalley also had a 68, along with compatriot Andrew Bonhomme and Argentinas Miguel Carballo at the challenging 7,469-yard Moonah Links course on the Mornington Peninsula near Melbourne.
Americans Ben Dickerson, Kyle Reifers and Josh Teater were a stroke back in a tie for sixth along with Australian Michael Sim and South Africas Garth Mulroy in the $600,000 tournament, co-sanctioned by the Nationwide and Australasian PGA tours.
Summerhays, who had seven birdies and three bogeys, and Haas said the layout commanded respect in the blustery conditions on Australias southeast coast.
The wind changes so much, Summerhays said. You need to play smart, you need to try and stay away from the trouble.
Added Haas, Its not an easy golf course ' there are some good players shooting some bad scores.
One of those was South Korea-born New Zealand amateur Danny Lee, who won the Johnnie Walker Classic by a stroke last weekend in Perth to become the youngest winner on either the European or Australasian tours.
The 18-year-old Lee, who plans to turn pro after the Masters, had a share of the lead at 2 under after 12 holes but dropped four shots, including a double-bogey 6 on the 9th, to drop to 2 over.
He was tied with defending champion Ewan Porter and veteran Peter Fowler.
OMalley, who first gained international recognition when he won the 1992 Scottish Open but hasnt won a tournament since the 2005 New Zealand PGA, is hoping his experience on the links course will help him end that drought.
The more I play it Im finding different ways to get around the golf course, he said. Theres a lot of thinking involved in playing the course.
There are a few holes I think are a little bit severe in the driving areas. Its certainly a challenge but the way its set up this week is pretty good.