'No threat' before WA jetty collapse

A 112-year-old jetty on Rottnest Island that partially collapsed was not part of the tourist hotspot's core infrastructure and there had been no indication of a risk, the West Australian tourism minister insists.

A 48-year-old British mother, her 11-year-old son and a female relative, 63, from Perth were injured when a slab of concrete gave way on the Army Jetty last month.

Speaking for the first time since the incident, Tourism Minister Paul Papalia said the jetty had been deemed unfit for boats and vehicles, but engineers had considered it suitable for pedestrians, including fishing.

"It was an unforeseen circumstances that the thing collapsed because the last engineer's report indicated that it was safe for pedestrian use," he told reporters on Wednesday.

"This was not a core bit of infrastructure that was used for anything on the island.

"It's now blocked to pedestrian access so there's no threat to anybody."

An independent inquiry into the collapse is expected to be completed this month.