Both riders starred and suffered at the 2017 Tour de France with Gesink crashing out after finishing second on Stage 8 while Bennett's momentum was brought to a halt with illness on Stage 16.
Both riders are known for their climbing ability and could feature on Stage 2 to Stirling as well as the penultimate stage on Willunga Hill.
“Gesink has had two top ten general classification results at the TDU, eighth in 2017 and sixth in 2014 so it will be interesting to see what his return to racing will deliver in terms of GC aspirations and results,” race director Mike Turtur said.
New Zealander Bennett caught the imagination of fans with his engaging personality and gritty riding which saw him battling to stay inside the top-ten before he was forced to abandon.
Also wearing the yellow and black of Team LottoNL-Jumbo will be Maarten Wynants, Robert Wagner, Enrico Battaglin, Daan Oliver and Tom Leezer.
Lotto-NL Jumbo for the Santos Tour Down Under
Maarten Wynants (BEL), Robert Wagner (GER), Enrico Battaglin (ITA), Daan Oliver (NED), George Bennett (NZL), Tom Leezer (NED) and Robert Gesink (NED).