The revenue department has asked tax officials to scrutinise the mismatch in services turnover numbers provided by businesses in income tax returns and service tax returns for 2015-16 and 2016-17 fiscals.

Central Board of Indirect Taxes and Customs (CBIC) Chairman P K Das in a letter to field formation stated that there was a considerable gap of ?12 lakh crore between the turnover on account of services as per the ITR/TDS (tax deducted at source) data and the value of services declared in the corresponding service tax returns for fiscal 2015-16.

Mismatches were also noticed for the financial year 2016-17, for which data is being shared with the field offices.

"... the sheer magnitude of the mismatch is a pointer to the possibility of revenue leakage which cannot be ignored," Das said, asking the tax officers to quickly verify the data and report it to the CBIC.

The mismatch in ITR and service tax returns has come to notice in respect of permanent account numbers (PANs) that are either not at all registered under service tax or PANs which are registered but did not file the service tax returns.

In some cases, there is a value mismatch between the turnover declared in ITR or TDS and the service tax returns.

Service tax was subsumed into the goods and services tax (GST) with effect from July 1, 2017, and the period under scrutiny is the last two financial years before the new indirect tax regime was rolled out.

Net service tax collections during 2016-17 stood at ?2.54 lakh crore as compared with ?2.11 lakh crore in 2015-16.