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. Interacts (via N-terminus) with spn-A/Rad51. Expressed both maternally and zygotically at all stages of fly development. Eggs and embryos exhibit variable alterations along the dorsal-ventral and anterior-posterior axes. There is a reduction in the level of meiotic recombination and an increase in the frequency of non-disjunction. Larvae have increased sensitivity to ionizing radiation and MMS. Belongs to the SNF2/RAD54 helicase family.