This will depend on if you are moving overseas short term or long term.
As novated leasing is only in Australia, if you are leaving long term, you will need to terminate and payout your novated lease. You can payout the novated lease by selling your car. Any shortfall between the lease payout and car sale price will need to be paid by you. if the sale price is higher than the lease payout then you get to keep the profit on sale.
If you are leaving short term and you are remaining in the employment of the same organisation they will continue to pay your novated lease, then your lease will be not be affected.