(Reuters) - Australian bourse operator ASX will defer the day's settlements to Monday after its Clearing House Electronic Subregister System (CHESS) software broke down and it was unable to resolve issues, it said on Friday.

The stock exchange operator said that it was receiving trades from approved market operators, but demand and registry transaction processing have been put on hold.

It added that no settlements took place on Friday due to a "CHESS batch settlement delay".

ASX's aging all-in-one CHESS system usually settles a trade two business days after a buyer and seller agree to the trade by arranging for money transfers.

Along with settlements, CHESS electronically registers the ownership of shares on its subregister.

"ASX is making every effort to identify the root cause and will share any developments as soon as they are made available," the company said.

It added that it had started the process to reschedule instructions from the CHESS settlement batch to Monday.

The outage comes after the S&P/ASX 200 benchmark index ended 1.2% lower - its lowest level since mid-September.

ASX had been looking to replace the CHESS software using blockchain-based technology but abandoned the overhaul in November 2022, six years after it was announced, citing concerns about the product's complexity and scalability.

Last year, it hired India's Tata Consultancy Services to overhaul the software, opting for a two-stage product-based route that will conclude by 2029.