Nannes will join Ryan ten Doeschate, Otago's other overseas professional, in the team.
After starting his international career for the Netherlands, Nannes went on to spearhead the Australian Twenty20 attack. In 2010 he was the leading wicket taker with 14 wickets at the World Twenty20 in the Caribbean.
Known for hs raw pace and aggressive bowling, Nannes has 246 wickets from 203 Twenty20 matches at an economy rate of 7.28.
Among the teams he has played for are the Delhi Daredevils, Chennai Super Kings Middlesex and Surrey and the Melbourne Renegades.
Volts coach Dimitri Mascarenhas said: "It is great to have Dirk on board with his wealth of experience and proven wicket taking ability. Dirk has been successful in different conditions all over the world.
"We have a number of young bowlers in our squad and the opportunity for them to play and train alongside Dirk will be fantastic for their development. We are delighted that our Twenty20 campaign fits in with Dirk's schedule and look forward to him being a huge factor in the success we are looking for in this competition".
Nannes and ten Doeschate will join the squad during their four-day game in Napier and be available for the first game of the Georgie Pie Super Smash on 1 November.
The Volts selectors also named the following teams for warm-up games against Canterbury, Scotland and Ireland at Lincoln next week.
October 19/20 v Canterbury at Rangiora (Roald Badenhorst, Nick Beard, Michael Bracewell, Mark Craig, Derek de Boorder, Ryan Duffy, Tipene Friday, Aaron Redmond (c), Brad Rodden, Hamish Rutherford (vc), Bradley Scott, Neil Wagner, Sam Wells)
October 22/23 v Scotland and Ireland at Lincoln (Roald Badenhorst, Nick Beard, Michael Bracewell, Derek de Boorder, Jacob Duffy, Ryan Duffy, Josh Finnie, Tipene Friday, James McMillan, Aaron Redmond (c), Iain Robertson, Hamish Rutherford (vc), Jesse Ryder, Bradley Scott, Sam Wells)
