What controls should be implemented with petty cash?

Authorization but Dual if exceed certain limit set by the company locker double checking

the controls should be implemented with petty cash register all cash receipt and expenses in cash movement form daily follow up for petty cash custody daily reimbursement expenses daily cash inventory from cashier and monthly from mangement

1.Petty cash received is checked, recorded, and physically secured.2.Petty cash expenditure, offset against the petty cash float, is in accordance with the types of expenditure permitted by the Payments manual, and supported where appropriate by valid receipts.3.Staff authorised to count the petty cash are preferably not those keeping the cash float.4.Petty cash floats are reconciled monthly.

initial control at the time of sanctioning, it should be duly authorised and recorded.
next up the balance in hand should be reconciled daily if possible by a person other than one handling the cash.

Along with above suggestion, you can also limit the payment from petty cash and keep a separate Petty Cash book to record the petty transaction.
Also, you can have a separation of duty between person handling petty cash and person recording the transactions in the accounting records.