A member of parliament has proposed building a wall around the City of Fremantle in a tongue-in-cheek jab at an incident at Monument Hill last week.

One Nation Upper House MP and member for the east metropolitan region Charles Smith posted his suggestion to Facebook on Monday, and asked his constituents: is it time to build a wall around the “socialist hell hole”, City of Fremantle?

Mr Smith's proposed boundary lines. Credit:Facebook

Mr Smith’s suggestion came after Fremantle Police confirmed they were investigating a bizarre act of vandalism where a man was seen emptying a bucket of excrement over the memorial plaques at Monument Hill.

It’s understood the man said it was his “personal prerogative” to desecrate the memorial before he left the scene, and police have since released a photograph of the alleged perpetrator.