What Is the Internal Revenue Service (IRS)? Auditing Process Explained

ByLouis Blythe Posted on

The Internal Revenue Service (IRS) is America’s most powerful tax authority—responsible for enforcing tax laws, collecting revenue, and keeping the world’s largest economy running. But what exactly does the IRS do, and how does its notorious auditing process work? While the IRS operates in the US, understanding its methods is increasingly relevant for Australians, especially as cross-border financial scrutiny intensifies in 2025.

The IRS: More Than Just a Tax Collector

The IRS is the United States federal agency charged with administering and enforcing internal revenue laws. Established in 1862, it now processes hundreds of millions of tax returns every year, manages tax refunds, and fights tax evasion on a global scale. Its reach extends beyond US borders—many Australians with dual citizenship, US investments, or business interests may have obligations to the IRS.

  • Global Influence: The IRS partners with the Australian Taxation Office (ATO) under treaties like FATCA (Foreign Account Tax Compliance Act), requiring Australian banks to report accounts held by US citizens.
  • Digital Transformation: In 2025, the IRS has ramped up digital tools for filing, compliance checks, and artificial intelligence-driven fraud detection, setting trends that other tax authorities are watching closely.
  • Taxpayer Services: From phone helplines to secure online portals, the IRS supports taxpayers but also wields significant enforcement powers—issuing penalties, garnishing wages, and, in rare cases, prosecuting criminal tax evasion.

How IRS Audits Work in 2025

For many, the word “audit” conjures up fear. But what really happens when the IRS audits a taxpayer? The process is structured, data-driven, and—contrary to myth—usually not random.

  1. Selection: Most audits are triggered by automated systems that flag anomalies—discrepancies between reported income and third-party data (like employer-reported wages), unusual deductions, or patterns that match known tax avoidance schemes. In 2025, AI and machine learning play a bigger role than ever in identifying audit targets.
  2. Notification: The IRS always communicates initial audit notices by mail, never by phone or email. The letter outlines the items under review and requests documentation.
  3. Documentation: Taxpayers must provide supporting documents—receipts, bank statements, contracts—related to the flagged issues. Audits may be conducted by correspondence (mail), at an IRS office, or, rarely, in-person at the taxpayer’s home or business.
  4. Resolution: After reviewing evidence, the IRS either accepts the return as filed, proposes changes (which may increase tax owed), or, in rare cases, refers the matter for criminal investigation. Taxpayers have rights to appeal.

2025 Policy Update: The US Congress boosted IRS funding in 2024, enabling expanded enforcement. The agency now targets high-income earners and complex offshore accounts more aggressively, while automated correspondence audits remain common for small discrepancies.

Why Australians Should Care About the IRS

Even if you’ve never set foot in the US, IRS policies can affect Australians in several ways:

  • Dual Citizens & Expats: Australians with US citizenship or green cards must file US tax returns, reporting global income. The IRS’s crackdown on unreported foreign assets means stiff penalties for non-compliance.
  • Australian Banks: Local institutions must report accounts held by US persons, increasing compliance work for both banks and their clients. The ATO and IRS regularly exchange data under international agreements.
  • Global Trends: The IRS’s use of data analytics and digital audits is influencing the ATO’s own compliance strategies. Expect more sophisticated, technology-driven audits in Australia as both agencies modernise their approach.

In 2025, cross-border tax compliance is no longer just a US issue—Australians with international interests must stay alert to evolving rules on both sides of the Pacific.

Key Takeaways for Australian Taxpayers

  • IRS audits are increasingly data-driven and targeted, not random.
  • Global information-sharing means non-compliance is riskier than ever, especially for dual citizens and those with offshore accounts.
  • The ATO is adopting many IRS-style techniques, so understanding these processes is smart preparation for all Australians.

Louis Blythe is a writer at Cockatoo Financial Pty Ltd and has been in the finance industry 2012. Since then, his mission is to make business loans and home loans easy for everyone. And each year, he continues to help more people with understanding interest rates, borrowing power and living expenses.