New safety harnesses introduced at Sydney Tower Eye have failed to prevent a second person taking their own life at the tourist attraction in just four months.
The new over-the-shoulder harness tethered at the back replaced a simpler "fall restraint belt" after a woman was killed at Sydney's tallest building in March.
On Sunday evening, a man taking part in the outdoor Skywalk tour near the top of the 268-metre-high building also jumped to his death.
Management of the Sydney Tower Eye defended its safety measures as being "well beyond global industry requirements".
"This is a very distressing situation for all those involved," Sydney Tower divisional director Rob Smith said.
"Our thoughts are with the family and friends of the guest, the Sydney Tower Eye team, and our guests."
In March, the woman was able to detach herself from the older "fall restraint belt" before taking her own life.
Sections of Pitt Street were shut down by police after the woman landed on a building canopy.
Since that time, Sydney Tower Eye has made a number of changes to its protocols including the introduction of the new harness.
"Sydney Tower Eye undertook a full and comprehensive review of its safety measures," Mr Smith said.
"Significant modifications to the harness equipment, safety attachments and clothing, as well as guest briefing protocols, designed to actively deter tampering have been introduced."
The Skywalk Tour remained closed on Monday, but the observation deck was open.
