Factory Act in Thailand: A Compliance Guide for Foreign Manufacturers

What the Factory Act in Thailand Covers

The principal legislation is the Factory Act B.E. 2535 (1992), as amended by the Factory Act (No. 2) B.E. 2562 (2019). It applies to industrial operations across Thailand and is enforced by the DIW under the Ministry of Industry. The Act regulates how factories are established, where they may operate, and how they must control safety, machinery, waste, and pollution.

Crucially, the law does not only ask whether you hold a licence. It also imposes ongoing operating standards. Therefore, a fully licensed factory can still breach the Act by ignoring environmental controls, altering machinery without approval, or failing to report incidents. In practice, compliance is a continuous obligation rather than a one-time approval.

Factory Categories and Licensing Triggers

The Factory Act in Thailand sorts industrial operations into three categories based on size and potential impact. The category determines whether you simply notify the authorities or must obtain a licence before you build or operate.

A business generally falls within the Act when it uses machinery of 50 horsepower or more, or employs 50 workers or more. Category 3 operators apply using form Ror Ngor 3 and, once approved, receive the licence known as Ror Ngor 4. Foreign-owned manufacturers should also remember a parallel point: the Factory Act sits alongside the Foreign Business Act and BOI rules, so licensing strategy and ownership structure must be planned together. Our guidance on BOI manufacturing and factory promotion in Thailand explains how these regimes interact.

Key 2019 Reforms Every Operator Should Know

The Factory Act (No. 2) B.E. 2562 took effect on 27 October 2019 and reshaped day-to-day compliance. First, it raised the definition threshold to 50 horsepower or 50 workers, up from the previous 5 horsepower or 7 workers. As a result, roughly tens of thousands of small workshops fell outside the licensing regime altogether.

Second, the amendment abolished the old five-year licence renewal cycle. A factory licence now remains valid for as long as the business operates, unless the operator ceases activity or transfers the licence. Third, the law introduced accredited private inspectors who may carry out factory inspections alongside government officials. Consequently, approvals and audits can move faster, although the underlying standards remain strict.

Common Factory Act Violations

Most enforcement action under the Factory Act in Thailand stems from a handful of recurring problems. Understanding them helps you build controls before an inspector ever visits.

• Operating without a licence: running a Category 3 factory before obtaining the Ror Ngor 4 licence.
• Unapproved changes: expanding capacity, adding machinery, or altering processes without notifying or seeking DIW approval.
• Environmental breaches: improper waste disposal, untreated effluent, air emissions, or noise exceeding permitted limits.
• Safety failures: inadequate machinery guarding, fire prevention gaps, or unsafe storage of hazardous materials.
• Reporting lapses: failing to submit required data or to report accidents and spills.

The penalties can be significant. For example, operating a Category 3 factory without a licence can attract imprisonment of up to two years, a fine of up to THB 200,000, or both, plus an additional daily fine while the breach continues. Other offences carry their own fines, and serious or repeated violations expose directors and responsible managers to personal liability.

DIW Inspections, Suspension, and Closure Orders

DIW officials, now supported by accredited private inspectors, may inspect a factory, request documents, and order corrective action. When they identify a breach, they typically issue an improvement order with a deadline. However, where the risk to people or the environment is serious, the authorities can move straight to stronger measures.

The Act empowers officials to suspend operations, order a factory to stop using specific machinery, or close the plant entirely until the operator fixes the problem. Notably, a suspension or closure order halts revenue immediately, so the commercial cost of non-compliance often dwarfs the headline fine. For a foreign manufacturer with supply commitments, even a short shutdown can trigger contractual penalties downstream.

How to Stay Compliant: A Practical Checklist

Foreign manufacturers can manage Factory Act risk with a disciplined, documented approach. The following steps reflect what well-run plants in Thailand do as a matter of routine.

• Confirm your category early: assess horsepower, headcount, and process risk before you lease land or order machinery.
• Secure the licence before building: for Category 3, file Ror Ngor 3 and obtain the Ror Ngor 4 licence before construction begins. Our overview of how to obtain a factory licence in Thailand sets out the steps.
• Notify before you change: seek approval for any expansion, relocation, or significant machinery change.
• Keep an environmental and safety file: maintain waste, emissions, and incident records ready for inspection.
• Train responsible managers: ensure the people named on filings understand their personal exposure.
• Audit annually: use internal or accredited inspectors to catch issues before officials do.

For investors who structure manufacturing through promoted projects, compliance also intersects with BOI conditions and customs obligations. Coordinating these workstreams from the outset avoids conflicting commitments later.

Appeals and Dispute Resolution

If the DIW issues an order you believe is wrong or disproportionate, you are not without options. Operators may submit representations, request reconsideration, and ultimately challenge administrative decisions through the appropriate appeal channels and the courts. Because deadlines are short and the technical record matters, early legal input is decisive.

In practice, the strongest position combines two things: a clean compliance record and a prompt, well-evidenced response. Where a closure threatens operations, swift action to suspend or vary the order can preserve the business while the dispute proceeds. Our team’s work in litigation and dispute resolution in Thailand covers exactly these regulatory and administrative challenges.

Frequently Asked Questions

Authoritative references: Department of Industrial Works (DIW) and the Office of the Council of State for the official text of the Factory Act.