Similarly, payments such as tax withdraw liquidity from the system as the payments flow through to a deposit in the Government's account. Conversely, government spending puts money into the system as the spending ends up as deposits in someone's bank account.
In normal times, the RBA aims to sterilise the impact of such transactions on system liquidity to ensure that the cash rate remains at the target set by the Board. But with system liquidity at a high level, this is no longer necessary. As a result, ES balances will fluctuate with these Government flows.