using ARIN assigned address in Asia

Hi, I have a question which was originally I was asked by my client. Our client has IP address space that was originally assigned from ARIN. Their address space is a big enough to separate to /20 each. I am not sure about internaltionl IP address assignment. They would like to use front half (/20) in North America. And, they would like to use the other half of the address space (/20) in Asia. Is there any problems doing this? thanks, Kenji