Applying for financial hardship or being approved for a hardship variation will not impact your credit score. A Financial Hardship Indicator (FHI) will appear on your credit report and remain there for one year if a hardship variation is approved. This will not impact your credit score, but this will be visible to other lenders, who may take this into consideration.
Missing payments, or having defaults registered at the bureau, will have a bigger impact on your credit score, and will be visible to other lenders longer, than having a FHI registered. Financial Rights Legal Centre (FRLC) has an insightful fact sheet on how your credit may or may not be affected by financial hardship.