The third round of the Ricoh Women’s British Open ended in drama on Saturday when the leader, Sun-Ju Ahn, was given a two stroke penalty on the final hole at Royal Birkdale Golf Club.

Ahn was taking her third shot from an uphill lie within the bunker short and left of the 18th green when television crews reported that she had used her feet to move the sand down the side of the bunker in an effort to get her feet on the same level and she was penalised under decision 13-3/3. She viewed the TV coverage of the incident and graciously accepted the penalty.

The 26-year-old Ahn, with 23 professional wins on the LPGAs of Japan and Korea, had birdied the third hole and bogeyed the fifth before picking up three birdies on the back nine, at holes 13, 15 and 16. She then made a par on the last for a 69, which would have seen her finish on five-under-par, but after the application of the two stroke penalty, her third round score was revised to 71 for a total of three-under-par.

That left her one stroke behind fellow South Korean Inbee Park, who shot 68 for a total of four-under-par, and alongside Suzann Pettersen and Shanshan Feng in a share of second going into the final round. Amelia Lewis and Julieta Granada share fifth place on two-under-par going into the final round, while there are seven further players, including England’s Charley Hull, a stroke further behind in a tie for seventh place.

Of the two Australians remaining in the field, Nikki Campbell posted a one over par 73, which included four bogeys and three birdies. All of Campbell’s birdies came in the last six holes, which was a nice way to finish. The two-time winner in Japan is at six-over for the tournament and in a share of 42nd position.

Sarah Kemp, who was playing alongside her fellow compatriot, signed for a 74. Kemp’s round included five bogeys and three birdies. The Sydneysider is at seven-over and tied for 47th position.

“It’s disappointing but it’s my mistake,” said Ahn. “I still have a day to go and I have to stay focused and try my best tomorrow. I didn’t know about the rule but all I was trying to do was make a stance. I’m surprised by it, but if that’s the rule, I just have to abide by it and refocus.

“The ball was placed on a very upslope lie, so it was hard to make a stance. So what I was trying to do was fix a stance but after the review it was determined that I used my feet to try to make an even lie. But you know, my intent wasn’t to break the rules. It was just to set my feet firm in the sand just to be able to make the shot. But if that’s the rule, there was no intent and I can’t do anything about it.”

Four-time major winner Park, who won the first three majors of 2013, could celebrate her 26th birthday by putting herself in the perfect position to win the championship for the first time.

Park said: “We can see from the scores that it’s moving day. The first two days I didn’t hit the shots well enough to get the results I wanted but today my ball striking was great today and I didn’t miss any greens.\"

“A couple of three putts for a bogey and I missed a short putt for a birdie on the last. Those three shots are left out there but I got off to a great start. The first four holes here are really difficult but I had a great start and am in a great position for tomorrow.”

Pettersen, who claimed her second major victory at last year’s Evian Championship, was back in the hunt following a round of 68, containing three straight birdies from the sixth hole, two bogeys on 13 and 15, an eagle on 17 and a birdie on 18.