Iranian oil shipments into China are set to fall in the near-term after new U.S. sanctions on a refiner and tankers, driving up shipping costs, but traders said they expect buyers to find workarounds to keep at least some volumes flowing.

Iran is operating a ghost fleet to sell oil to China in violation of existing sanctions, which U.S. officials seek to stop with the help of new sanctions.

Washington has issued new Iran-related sanctions, including a Chinese "teapot," or independent refiner, and vessels that supply oil.