Probably only slightly, and only temporarily. A company called Veda is the main provider of credit ratings in Australia, and their list of data used (in calculating an individual’s credit score) is topped by payment defaults. Next comes the number of credit enquiries lenders make about you, and then the number and type of credit enquiries and requests for credit you make yourself. So, while the size of the credit you apply for may have an impact on your rating in the short term, any substantial credit you actually use and repay within the agreed conditions is more likely to improve your score in the long term.