Engineers have been unable to pin down exactly why one of The Strand waterfront's waka sails sculptures crashed to the ground last month.
The 18-metre-high stainless steel sculpture sheered off its foundations in moderate winds on September 10, smashing through a fence and blocking the railway line.
Steve Webb, the Tauranga City Council's parks team manager, said the report on why the sculpture failed identified that it was a fabrication or design issue. "But it was not definite on exactly why it failed."
Mr Webb said it could have been poor-quality steel or the welding, but it was not because of excessive wind. More tests would be needed, including X-rays, to conclude whether the steel met quality specifications or if the welding was at fault.
The $200,000 sail was one of two erected in 2004. They were to have been joined by three others to represent the Southern Cross star cluster, but were never ordered.
Mr Webb was unsure why the project was not completed or whether the the first two waka sails were still covered by a manufacturer's warranty. The council was looking at an insurance claim.
The remaining waka sail was taken down and put into storage after an inspection revealed signs of cracking around the base.
A report is being prepared for the council on options for the sculptures.