Aug 4 (Reuters) - It would be reasonable for the Federal Reserve to increase the size of a stopgap liquidity facility that Japanese authorities are eyeing for use in their effort to prop up the yen given the bond market has grown since the facility was launched, Treasury Secretary Scott Bessent said on Tuesday.

"The facilities that the Federal Reserve has, whether it's the FIMA (Foreign and International Monetary Authority) facility or the swap lines, the purpose is to protect the U.S. economy and to keep any volatility offshore, prevent it from happening before it reaches our U.S. shores," Bessent said in an interview on CNBC two days after confirming a joint U.S.-Japan intervention last week to support the yen.

When the FIMA facility was created in 2020, Bessent said, "the size of the bond market was much smaller then, so I think it would be reasonable for the Fed to consider up-sizing the facility."

"I'm happy that the Japanese government wants to use it and draw on it, and it's a completely secure lending facility. We have swap lines outstanding, so it's really no different than a swap line - that the country posts collateral and we lend them the money to intervene, in this case," Bessent said. "And I think it is a very robust facility, and I think it was set up for occasions just like this."