Customs officials have been criticised for failing to crack down on criminal gangs who dodge alcohol tax at an estimated cost to the Treasury of more than £1 billion.
MPs claimed HM Revenue and Customs appeared to be reluctant to prosecute offenders after they found just 20 successful cases had been brought over the four years to 2009/10.
Although HMRC has put the gap between the amount of alcohol duty due and the amount collected at around £1.2 billion, the Public Accounts Committee criticised it for failing to assess the tax gap for wine despite previously pledging it would.
The cross-party spending watchdog also found the department did not have good enough information about how effective it was at tackling the problem and failed to make the best use of intelligence and technology to detect and prevent evasion.
The PAC's Richard Bacon said: "HMRC's drive to tackle alcohol duty evasion is being seriously hampered by a lack of information. Alcohol fraud is big business. The department estimates that the gap between taxes due on alcohol and the amount actually collected might be as large as £1.2 billion.
"The department does not, however, have enough reliable information on the returns from tackling different types of alcohol duty evasion. It cannot say, therefore, whether a more effective targeting of its resources might not secure a better return on its investment.
"It is unacceptable that the department has still to produce an estimate of the tax gap for wine, despite a commitment to this committee's predecessors to do so. The absence of information on the scale and nature of wine duty fraud undermines the basis on which the department directs its resources to tackling the problem.
"Since the criminal gangs who perpetrate major alcohol duty fraud operate across national boundaries, the department needs to strengthen its intelligence by developing better links with the industry, the UK Border Force and other EU member states.
"The department seems to be reluctant to prosecute offenders. Over a recent four year period, there were successful prosecutions in no more than six cases a year. This sends the wrong message to perpetrators and the wider public about the department's commitment to reducing alcohol duty evasion. It should give more weight to the deterrent impact of pursuing perpetrators through the courts."