You can apply for an employment visa if you are: 

1. Officially employed in Belize. 
2. Conducting consultation visits.
3. Commercial representatives of foreign companies.
4. Foreign media personnel.
5. Technical professionals performing work in Belize.

Persons eligible for approval of a Temporary Work Permit must belong to one of the following categories.

1. Professional workers (holders of a university degree).
2. Managers; Directors; Director.
3. Technical Supervisory Officers; Technical Officer.
4. Real estate agent.
5. Technical workers.
6. Cashiers; Supervisors.
7. Mechanic.
8. General workers.
9. Banana, sugar or citrus growers; Agricultural laborers.
10. Cook.
11. Caretakers.
12. Maintenance; Cleaner.
13. Farm foreman; Farm helper; Other non-agricultural workers; Seasonal agricultural workers; Self-employed workers in the agricultural industry.
14. Self-employed workers.
15. Manager; Business owners; Business supervisory manager; Technical manager.
16. Owners or managers of agricultural holdings.
17. Entertainers; entertainers performing in groups of 2 or more persons, but less than 6 - (performing one week or less); entertainers performing in groups of 6 or more persons (for one week or less); entertainers performing alone (one week or less).
18. Religious, cultural or educational volunteers; Pastors; Missionaries; Qualified music teachers.
19. Import and export merchants.
20. Peddlers.
21. Self-employed salesmen.
22. Waitresses and domestic employees.
23. Permits are granted only in exceptional cases.

2) If you intend to work in Belize, you must apply for a Temporary Work Permit and you must reside in Belize. 

Documents:

1) Filing the application:

• File the application at the Department of Labor. 
• If you are employed, your employer must file on your behalf.
• If you are self-employed, you must file it yourself.

2) Notification of Application Status

• Within 30 days you will receive a call from the Department of Labor to inform you of the status of your application.
• If your application is approved, you must go to the Department of Labor office to receive a copy of the approval letter.
• In case of denial of the application, you must go to the Department of Labor Office to receive a copy of the denial letter and report to the Immigration Office to update your legal status.

3) Visiting the Immigration Office

• You must go to the Immigration Office and bring the approval letter with you in order for the permit to be processed.
• You will be informed of the temporary work permit fees to be paid at the Immigration Office.
• You will be informed that you must go to the nearest Belize Revenue Service to apply for an income tax letter.

4) Issuance of the permit    

• You will need to present your valid passport, proof of payment and income tax letter to the Immigration Office as indicated in the approval letter.
• The permit is issued immediately upon confirmation of payment.
• Then go to the Social Security Office to apply for your card.
• You must apply at any Department of Labor Office. For more information on the requirements and application process, visit the nearest Department of Labor Office or click here to visit the website. 
• To file an application for a Temporary Work Permit with the Department of Labor, you must be in possession of a valid passport and a valid visa for Belize.
• If your application is approved, you will need to go to the Immigration Office closest to the Department of Labor office where you filed your permit application.

More information here.