The German won her eighth consecutive match of the new season, coming from 3-1 down in the second set to beat qualifier Giorgi 6-2, 6-3 in the semi-final.
The 2016 Australian Open champion is in superb form going into this year's event,having also won all four singles at the Hopman Cup, but knows she faces a big test against Barty on Saturday.
"Ash is a great player. She played unbelievable last year," Kerber said.
"I played the last match of 2017 against her, so it was not so long ago. I know what to expect."
Barty will play in her first home WTA final on after overcoming compatriot Daria Gavrilova 3-6, 6-4, 6-2.
Barty lost her serve six times in a match which included 13 breaks of serve - although the Australian took confidence from the win over her opponent.
"It's nice getting a bit of confidence going into our biggest tournament for us," Barty said of next week's Australian Open.
Gavrilova's frustration with her own serving became evident in the ninth game of the set when, soon after leveling at 4-4, she double-faulted twice and received a code violation for smashing her racket.