The relationship between our Constitution and other laws
The Constitution is a law passed by Parliament and it is the highest law in the land. All other laws must follow it. Other laws can be divided into statutes, common law and customary law:
Statutes are laws, which are made by government. Laws made by the national parliament are called Acts of Parliament. Laws made by Provincial legislatures are called Ordinances, and laws made by Municipal Councils are called by-laws.
Common law means laws that have not been made by parliament or any other government. They are unwritten laws. Common law is based on Roman Dutch law (laws that were brought by the Dutch when they arrived in South Africa). The courts used these laws and developed them when they made decisions.
Customary laws are also unwritten laws. They are laws that apply to certain cultures or ethnic groups.
All these laws have to follow the Constitution. In other words, they cannot go against what the Constitution says. So, new laws must follow the Constitution and the government must change old laws or parts of old laws if they don't follow the Constitution. If a customary law or common law goes against the Constitution then a court will say it is invalid. In other words, it can't apply in the situation.
Source: www.paralegaladvice.org.za/docs/chap01/04.html