This is a follow-up comment to my previous answer which you can ignore for I have included it in here. My earlier answer was done on the spur of the moment without in-depth thinking. As I said I need to check the text. So here is the full answer.
If you mean creator God to be the Christian concept of God, then your question will have no answer because this creator God was not "known" during the Buddha's time; in fact this God was not "created" yet, bearing in mind that Christianity came into being during the time of Jesus. Even if you mean a Judaic God, it was also not known in India during the Buddha's time.
Actually when one asks a Buddhist of his opinion about the Creator God, it will be a nondescript terminology because this Creator God idea was never a contention in Buddhist teachings. So to believe or not is never a problem to the Buddhist. It is just like asking a Christian whether the scriptures reject the concept of Nibbana. As far as he is concerned this concept is irrelevant and a non-entity. He will tell us that what is not written in the Bible is not truth. There is not a need to reject specifically, as such.
Likewise, if we study the Buddha's teachings we will come to realize that if we agree with the Buddha, then the creator God is irrelevent and a non-entity. The Buddha did not need to specifically refute, because as far as he was concerned the creator God idea was not in his teachings. As a matter of interest, there was indeed mentioned by the Buddha of a different Creator God which in Brahmanism (the original form of present Hinduism) is called Brahma, the Creator God. In the first sutta of the Digha Nikaya, called the Brahmajala Sutta, it is said along these lines:
"DN I (Sutta 1) Brahmajala (The Perfect Net)
The world system will pass away. Then after a long time, this world system begins to re-evolve. Palace of Brahma appears but empty. Then some being falls from the World of Radiance and comes to live in the Palace. Being lonely he wishes that other beings might come to join him. Just then other beings also fall into this Palace. This Brahma thinks that he has created the others, and the others also think likewise, and Brahma being regarded as the Creator."
So in this context, the Buddha did expressly state that the concept of Brahma as the creator god was false. In the Judaic context we may conclude that it is implied.