We only have an unsourced statement on Wikipedia to say it is, but the line "gimme the thing you got in your belly" does point in that direction... Possibly the patois verse sheds more light on it. Also there may have been other verses which weren't recorded, and there may have been well-known events which were only alluded to in the song.

I checked in the book that comes with the "West Indian Rhythm" box set, which says:

The Growling Tiger (Neville Marcano) recalled that "Netty" was "a girl from behind the bridge" (east of the Dry River in Port of Spain). She deported herself as though she was having a baby but never delivered the infant, this being an important part of the song's satirical content.