Australia's Su Oh continues to shine at the LPGA Tour's CME Group tour championship in Florida, inside the top five as the elite players of the world's best women's tour go into the weekend.

Melburnian Oh, 23, augmented her opening 69 at Tiburon Golf Club in Naples with a 67 today, including seven birdies.

It left her at eight under overall, just four shots from the lead held by South Korean Sei Young Kim at 12 under.

Oh has never won an LPGA Tour event, so this would be a big one, not least because the first prize cheque is the biggest in women's golf history -- $US1.5 million.

The tour championship is worth $US5 million, but only a limited field of 60 get to play. Plus the tour abandoned the previous notion of a separate $US1 million bonus pool and funnelled that money into the overall prize pool this year, giving everyone a chance of winning.

Oh has had a breakout year in her fourth season, but it will not surprise anyone in the game. Having emigrated from Korea to Australia with her parents when she was seven, she was a world class amateur and qualified for a Women's Australian Open at Metropolitan when she was just 12, going on to join Minjee Lee in a winning Australian World Amateur Teams Championship side and representing Australia at the 2016 Olympic Games.

Her only previous victory in a professional tournament was in the Australian Ladies Masters at Royal Pines in 2015, but she has had a string of strong performances on the main tour this year.

Queenslander Katherine Kirk (tied-26th) is also having a decent week in Florida, but world No.5 Minjee Lee (43rd) and major champion Hannah Green (49th) are well back.

Meanwhile, New South Welshman Rhein Gibson continues to press for his maiden US PGA Tour victory in Georgia, sitting tied second after two rounds of the RSM Classic.

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