Rain delayed the start of play by several hours on Saturday with the round finishing near dusk.
Koepka was at 12 under overall at the Sentosa Golf Club.
Four players were three strokes behind the American: Mexico's Abraham Ancer (67), compatriot Matthew Wolff (65), Thomas Pieters (67) of Belgium and Pole Adrian Meronk (66).
.— LIV Golf (@livgolf_league) @BKoepka is firing on all cylinders in Round 2💪He's T1 with Pieters on 10-under 📈#LIVGolf @SmashGC pic.twitter.com/ojBy06VBFHMay 4, 2024
Four more were just four strokes behind Koepka heading into Sunday's closing round. That quartet includes Australian's Marc Leishman and Lucas Herbert, who both shot four-under 67s.
Leishman enjoyed a blemish-free round while his Ripper GC teammate Herbert combined six birdies with two bogeys.
Another Aussie in Cameron Smith (65) is six under while Jon Rahm, who has yet to win after joining LIV in December, was seven strokes off the pace after a 68.
Rahm, however, is the only player to have finished in the top 10 in all six events in 2024.
The next LIV tournament is June 7-9 in Houston, Texas.
With AAP.