Things could get much tougher quickly, with a potential second-round meeting against wild-card entry Jo-Wilfried Tsonga, who he beat in the 2008 Australian final, and with Denis Shapovalov in the same section.
Spaniard Rafael Nadal and defending champion Roger Federer were seeded second and third respectively.
Federer has won the title the last two years and has an extra carrot having gone into the season on 99 career singles titles. Murray is playing in Australia under his protected ranking of world number two, which is used to help players who have suffered long-term injuries.
A hard first-round draw for Murray sees the world No 230 face 22nd seed Bautista Agut, though the five-time Australian Open finalist will be buoyed by his 100 per cent record against the Spaniard.
Australian Nick Kyrgios takes on 16th seed Milos Raonic in arguably the biggest first-round match-up in the men's draw. If it would happen defending this title, I would gladly accept it.More news: James Harden's Clutch Three Closes Out Wild Game Between Rockets and Warriors
Second-seeded Angelique Kerber, who won the Australian and U.S. Opens in 2016 and added the Wimbledon title a year ago, is in the same half as Wozniacki and has 2017 U.S. Open champion Sloane Stephens in her quarter.
"I can't believe it's been a year already", Dane Wozniacki said at the draw ceremony.
Second seeded Nadal begins against Australian James Duckworth, fourth seed Alexander Zverev faces Slovenian Aljaz Bedene while last year's runner-up Marin Cilic has a tricky encounter with Australian Bernard Tomic.
Defending champion Wozniacki, who broke through for her maiden Grand Slam title with victory over Halep in last year's final, is in line to face former victor Maria Sharapova in a mouth-watering third round showdown. Murray opens against No. 22-seeded Roberto Bautista Agut.
The three-time grand slam champion then offered a kind gesture by saying: 'If you'd like to come along and watch my match on Monday or Tuesday I'll sort you a ticket'. "I feel like these courts are suited for me, so it's incredible to be back".