Clause 51 relates to the repayment of certain COVID-19 benefits.
If a benefit is received, it's generally included in your income. If you have to repay it, the general rule is you get a deduction for the repayment in the year that the repayment is made. This measure would allow for a deduction in the year when the COVID-19 benefit is received rather than in the year in which it's repaid. That can help offset the income with the deduction. It's for cash flow benefit purposes. It can also help in later circumstances, when in later years the individual who received the amounts doesn't have any taxable income to utilize the deduction.