SYDNEY, Dec 5 (Reuters) - The Australian Securities Exchange defended its public statements about a failed overhaul of its ageing trading platform with blockchain technology at a parliamentary hearing on Monday, but acknowledged it prioritised the wrong features.

The operator of the world's 13th-largest stock exchange has been facing criticism since "pausing" a project last month to rebuild its trading, clearing and settlement software with a distributed ledger system, also called blockchain, some seven years into the project, resulting in a charge of up to A$255 million ($169 million).

Under a previous CEO and chair, the company told shareholders and stockbrokers that the new system was on track, but the schedule was repeatedly postponed, a parliamentary committee made up of senate and lower house representatives said.

"You do have my commitment around transparency," said ASX Chair Damian Roche, who started in 2021.

"I believe that we were being transparent and engaging with our regulators on the status of the project at all times."

ASX CEO Helen Lofthouse, who started in August, said the company had prioritised "functionality" of trading-related features. This meant some problems with non-trading elements like security and scalability appeared "quite late in the project", she said.

"That's clearly problematic and I fully accept that," Lofthouse told the committee.

Roche, the ASX chair, confirmed the ASX board had no committee to oversee technology until after he became chairman, despite the exchange undertaking one of the world's highest profile technology projects since 2015.

Asked if the project may have been improved if such a committee was formed earlier, Roche said: "I would agree with that."

Australian Securities and Investments Commission Chair Joe Longo told the committee that ASX's discovery of problems with the project so late was "altogether unsatisfactory". (Reporting by Byron Kaye; Editing by Cynthia Osterman)