I think you are right on the money.
laws = undang-undang
rules = peraturan
regulations = aturan/perintah (depand on the context)

Here is what I found from dictionary.law.com:
1. law n. any system of regulations to govern the conduct of the....
2. rules n. a set of procedural regulations adopted by....
3. regulations n. - rules and administrative codes ....


If you translate , rules and regulations , it will be "aturan dan peraturan". It cannot be undang-undang dan peraturan, or undang-undang dan aturan. But because in Malays, in most cases, the second word come before the first word, I would say rules = peraturan and regulations = aturan.

sophie,

- in legal terminology, i think that's how it's written. maybe hanim can confirm. [i've often used the same when translating business and finance, esp when reference is legal.]

- can also be written: undang-undang, rukun dan peraturan

Although these are sometimes used interchangably, without context, it should be "undang-undang, rukun, dan peraturan"

For everyone's info,
law = undang-undang (usually) OR hukum (as in Hukum Boyle for Boyle's Law)

rules = perintah as in "direction by court" (rule nisi = perintah nisi), rukun "as in legal principle" (rule against perpetuity = rukun mencegah kekalan), kaedah (rule of pleading = kaedah pliding)

regulations = peraturan (generally) or aturan (as used on Birt certs) Pls refer to Istilah Undang-Undang DBP (1997) or Istilah Undang-Undang 4th Ed, THomson.

As Yamyam said, the context would tell which should be used when.