Victoria’s Suburban Rail Loop Authority has spent $126 million during its first 18 months of operations, with the “key achievement” being the laying of a 630-metre sewer pipe, annual reports reveal as experts call for it to be paused.

The $125 billion project, which would follow a 90-kilometre loop from Frankston in Melbourne’s south-east bayside to Werribee in the western suburbs, has faced fierce criticism from experts, while Victoria’s auditor-general has previously raised concerns that the project was not subject to an adequate business case assessment.