I think the wasps are the Paper Wasp, Ropalidia revolutionalis.
The swarm of wasps have built a long thin paper nest hanging down from the Serissa branches. An egg is laid in each cell, but I'm not game enough to try and take a look. These wasps can give quite a painful sting if you disturb their nest.
I've also found another next hanging from a branch of the Mussaenda glabra in one of the front garden beds. These little fellows have been very busy!!