Create a general ledger Liability account for long service leave using Default Tax Code X.

Create a general ledger Expense account for long service leave using Default Tax Code X.

You should add a General Journal using GST Type Purchase (it is an expense)
CR 2-XXXX Long Service Leave Liability Tax Code X
DR 6-XXXX Long Service Leave Expense Tax Code X

How to
Create Similar or Recurring General Journals