Inland Revenue is warning thousands of people making bogus expense claims in their tax returns that they could face significant penalties.It says it has identified a coordinated scheme of people claiming expenses they should not, after staff noticed unusual returns being filed.Spokesperson Sarah Bourke said the investigation identified and stopped nearly 3000 fraudulent amended returns including 547 received on one night.People had told Inland Revenue staff that posts on social media offered to help with their expense claims."$151,787 of refunds were paid out before a new measure was put in place to stop the fraud while $4.015 million in bogus claims was stopped. Inland Revenue is taking action to recover the money with one individual already under an instalment arrangement to pay it back," Bourke said.She said the scheme seemed to spread through a community or workplace network."What initially appeared to be concentrated in the transport industry has broadened significantly to other areas across the country."As well several customers came into our Front of House in Auckland and Wellington earlier in the week wanting to reset their myIR passwords so they could amend their returns."They told IR staff the word in the transport industry was that there were people who knew how to get extra money and mentioned someone on social media offering to help people with the expense claims."Work is already underway to identify people promoting/running the scheme. If anyone is thinking they can make a quick buck by joining in the scheme they should think again. Inland Revenue is aware, can see what is happening and will take action. There are always consequences," she said.People who claim expenses that are not legitimate could be subject to sanctions, including a 150 percent evasion shortfall penalty and/or prosecution, as well as having to pay the money back.Sign up for Money with Susan Edmunds, a weekly newsletter covering all the things that affect how we make and spend money.