Complex sentence: The population is now set to plummet and there are concerns gangs such as mongrel mob or black power could overrun the town, this has occured in other small new zealand urban towns such as kawerau.
Split into simpler sentences: The population is now set to plummet and there are concerns gangs such as mongrel mob or black power gangs. This has occured in other small new zealand urban towns such as kawerau.