Hi,
Thanks for your query.
Special one-time cost of living tax credit is not taxable.
Some government grants are taxable and you receive a Tax slip for them and if they are not taxable you would not receive a tax slip.
"Government grants and subsidies
If you get a grant or subsidy from a government or government agency, you'll have to report it as income or as a reduction of an expense. Generally, a grant or subsidy:
For example, if you are a farmer and you received a payment to subsidize your income in a drought year, you would add the payment to your income. However, if you are a business which receives a government employment grant to hire more students, you would generally deduct it from the wage expense you are claiming.
Government assistance that enables you to acquire capital property does not increase your net income. However, for depreciable property, you reduce the capital cost of the property by the amount of the assistance received. For other capital property, reduce the adjusted cost base accordingly.
For more information, see interpretation bulletin IT-273R2, Government Assistance - General Comments."