The audit authority also said that the examination of 222 tests reports relating to five contracts revealed that 'the tests were not conducted in accredited laboratories'.

The report highlighted that contrary to its reputation, DMRC completed three lines in Phase one much after the deadline. The Inderlok-Rithala line scheduled to complete in September 2003 was actually completed in March 2004 - a six month delay.

Similarly, the Connaught Place-Central Secretariat line ended in July 2005 against its deadline of March 2004 - delay of 15 months. The Barakhamba-Indraprastha line too was delayed by 14 months, the audit body found.

The CAG report, which covered 2006-07 fiscal, was presented to the government last year but was not tabled in parliament.

'They (the government) deliberately delayed the tabling of the report on one pretext or the other. There were three sessions of parliament after we submitted the report,' said A.N. Chatterjee, deputy comptroller and auditor general told reporters.

'To hasten the project, quality control procedures were relaxed deliberately,' he said, adding: 'If these reports were presented in time, it would have been better as some of it has clear and direct linkage with what we are witnessing today.'

Six workers were killed and 15 others injured when an elevated section of the Delhi Metro track under construction at Zamrudpur in south Delhi collapsed early Sunday morning. The next day, six people were injured at the same spot when three cranes, being used to remove a steel girder that had got inclined, suddenly toppled over.