Hello All, Is their a standard netsuite functionality to block transactions/payments for sanctioned countries.

Not that I'm aware of. But it wouldn't be that hard to do a workflow or script to prevent customers/vendors set to certain locations/other fields from saving. Oracle/NetSuite would never do the actual checking of whether the business was sanctioned for you. You'd need some sort of third party service for that, and even then the ultimate liability is still usually on you/your company.