Involved in mitotic DNA repair and meiotic recombination. Functions in the recombinational DNA repair pathway. Essential for interhomolog gene conversion (GC), but may have a less important role in intersister GC than spn-A/Rad51. In the presence of DNA, spn-A/Rad51 enhances the ATPase activity of okr/Rad54 (By similarity). Interacts (via N-terminus) with spn-A/Rad51. Belongs to the SNF2/RAD54 helicase family.