Around 450 exporters are under the lens of the revenue department for possible misuse of supplementary drawback claims of Rs 15-20 crore over the last three years.
The move has been initiated following the detection of misuse of duty drawback benefits by some exporters.
Revenue department officials said the case came to light earlier this year when the department found some exporters were claiming supplementary drawback through special drawback rates, which had not been notified by the revenue department. Initially, the scale of the fraud was estimated at around Rs 8 crore.
In July this year the department referred the matter to the Central Bureau of Investigation (CBI).
An outsourced worker handling the online system for the Customs department was arrested after he was found to be using the login identity of Customs officers without their authorisation.
Further investigation by the CBI found manipulation in the software of the National Informatics Centre, the government agency that handles data systems for the Central Board of Excise and Customs.
When contacted, a CBEC spokesperson said the CBI had made some arrests in the case. National Informatics Centre officials did not comment on the matter.
Officials said the department had already recovered Rs 10 crore. Following the case, the CBEC has also asked its field formations for suggestions on how to beef up the security of the data systems.
The revenue department has begun issuing showcause notices to all exporters who have made supplementary drawback claims in the last three years, according to Ajay Sahai, director-general, Federation of Indian Export Organisations.
Since the fraud has been detected in the Indira Gandhi International airport, the department should first verify with Punjab National Bank (the nodal bank for drawback on exports from the airport) to see how many claims have been made by exporters, he said.
Several supplementary drawback claims were made since the drawback rates were increased by the department with retrospective effect. The cases where one exporter has made more than half a dozen supplementary claims on the same shipping bill are the ones that should be examined, he said.
There are two kinds of drawback the all industry drawback rates and the brand rate of drawback.
The all industry drawback rate takes into account the yield ratio, which is the duty suffered on the item vis--vis the export price, while the brand rate is fixed for a company for a particular product.
However, officials added that there was no proposal to shift the systems operations from the National Informatics Centre to another organisation.