A birdie blitz has fired Min Woo Lee into contention halfway through the PGA Championship at the beastly Oak Hill Country Club in upstate New York.

Once again revelling on the big stage after three straight missed cuts, Lee carded a three-under-par 67, to head up the Australian challenge five shots off the pace in Rochester.

The 24-year-old had the round of the day going after collecting five birdies in his first seven holes before his putter cooled off on a freezing cold Friday at the season's second major.

Lee dropped a shot at the brutal par-4 sixth - ranking this week as the most difficult major championship hole in the past 20 years - before missing a six-foot birdie attempt at the 13th and three-putting on No.15 for bogey.

Still, he was chuffed to have clawed his way back to even par for the championship, tied for 10th behind joint leaders Viktor Hovland, who also shot 67, Corey Conners (68) and Scottie Scheffler (68).

"It was really good. It's been a while since I was really proud of how I handled myself. It was a grind out there," the West Australian said.

"There were a lot of par saves that I needed to do just to keep the momentum up.

"It was very gritty out there, which is something I feel I've been lacking a little bit.

"But it's kind of nice to do that, especially at a major championship."

After playing in the final group on Sunday and ultimately finishing sixth at The Players Championship, then winning a round at the WGC Match Play to qualify for the Masters, Lee lost his way.

Doubts crept into his game but he was intent to go back to basics on Friday.

"I needed something to switch because I've been playing sluggish over the last few weeks, few tournaments," Lee said.

"I don't know what clicked. I just wanted to stop missing cuts and play well today. I was just really focused on what I needed to do."

Lee is making a habit of lifting for the majors, tying 14th on debut at Augusta last year and also sharing 21st and 27th spots at the British Open and US Open respectively.

"I don't know, I just like playing in front of a lot of people and being in front of a crowd," he said.

Cam Davis is the next best Australian, six back at one over, after a second-round 70.

Adam Scott is a further stroke behind and needs to play catch-up over the weekend to get back into the mix after another rough finish to his round.

Scott tumbled down the leaderboard from a share of sixth after leaking four shots in his last four holes in a four-over 74.

Scott had been in red numbers for most of the day until his late stumbles.

He also undid some great work on Thursday with a nasty double-bogey six at the last hole, having shared the lead.

Lucas Herbert, the only Australian to par the sixth in round two, rebounded from a first-round 75 with a 69 to make the halfway cut at four over, alongside reigning British Open Cameron Smith, who recorded a second successive 72.

But Jason Day and David Micheluzzi, making his major championship debut, both missed the cut.

Unable to reprise the golf that helped him break a five-year PGA Tour title drought last week in Texas, Day's second-round 72 left him at eight over, three shots outside the cut line.

Micheluzzi, with rounds of 76-73, was one stroke further back.