Can a tax accountant be sued for malpractice?

I am in the completion stages of an IRS audit and facing what could be a financial nightmare. Through the process it was discovered that due to income level there are deductions that were taken on investment property that I do not qualify to take until the properties are sold. The accountant made many errors that were not data errors as all the data was accurate, it was how he applied that data that created the audit. The IRS auditor is not assessing penalties due the the level level of mistakes that were made by the accountant and may assess penalties against him. I have been advised that he was incompetent in his work and has now created this financial situation. Looking for some advice on how to proceed if I can.