LPGA Tour rookie Amanda Doherty has posted a six-under 67 at Galgorm Castle Golf Club to take the first-round lead at the World Invitational at Antrim.

Doherty's seven birdies on Thursday helped her take a slender lead over four players at five under par after one round of the unique multi-course event.

Golfers will play one round at Galgorm Castle and one at Massereene Golf Club before the 36-hole cut. Galgorm Castle will host the final two rounds, with a second cut coming after 54 holes.

The event is tri-sanctioned by the LPGA Tour, Ladies European Tour and European Tour. A field of 132 men are also playing on the same courses, and the men and women are competing for identical purses of $1.5 million ($A2.1 million).

Doherty has a one-shot edge over Lauren Coughlin and Denmark's Emily Kristine Pedersen, who both shot five-under 67s at Massereene, and England's Georgia Hall and Ireland's Leona Maguire, who shot five-under 68s, at Galgorm Castle.

The twin-course system leads to some oddities. The leading Australians in the field are Stephanie Kyriacou, who is two under, and Karis Davidson, who is one under, though both shot 71. Su-Hyun Oh is one under after a 72.

The 24-year-old Doherty has yet to have a top-10 finish on tour, let alone a victory.

"I was really just trying to stay in the moment today, and I feel like I was just kind of in that mindset starting the day," Doherty said. "I stayed there and I stayed patient. I know it's kind of cliche, but it works."

Scotland's Ewan Ferguson leads the men's event. He is four clear of the field after shooting a nine-under 61. The best placed Australian, Dimitrios Papadatos, is two under and is tied 23rd.