what should i do

Every night I can hear my Neighbours going at it, loud moaning all through the night, it's got to the point where its waking our kids up, like I'm not joking 4-5 rounds a night, (lasting 20-30 mins a time) i can wake up in the middle of the night to moaning and cheeks clapping. I'm scared to tell them as we have a young family and their gang members. any advice please we are in south Auckland.