Yes, if you move to a country with which Iceland does not have a convention on international rights.

If you move to an EEA country, you will keep your disability pension unless all benefits are cancelled. Iceland also has an agreement with several other countries as well as the United States and Canada.

If you have a disability assessment and moved to the UK after the UK's exit from the European Union (Brexit), your payments will cease upon relocation. However, your disability assessment with TR (Social Insurance Administration) will not be invalidated. If you move back to Iceland or to other countries with which Iceland has an agreement, payments will resume upon confirmation of residence from the country of residence.

You can see more about the Contracting States here.