Plays a role in processing non linear or branched viral DNA intermediates in order to promote the production of mature packaged unit-length linear progeny viral DNA molecules. Exhibits endonuclease and exonuclease activities and accepts both double-stranded and single-stranded DNA as substrate. Exonuclease digestion of DNA is in the 5'-> 3' direction and the products are 5'-monophosphate nucleosides. Additionally, forms a recombinase with the major DNA-binding protein, which displays strand exchange activity. Interacts with major DNA-binding protein; this interaction increases the nuclease processivity of the alkaline exonuclease. Belongs to the herpesviridae alkaline nuclease family.