U.S. officials will press their Chinese counterparts on currency policy at high-level talks next week, and have not taken off the table the possibility that the United States may one day join a China-led infrastructure bank, a senior U.S. Treasury official said.

In comments to reporters on Thursday, the official, who asked not to be named, said China's yuan still appears undervalued despite a recent assessment by the International Monetary Fund that this was no longer the case.

"We see meaningful scope for further exchange rate appreciation," the official said in a briefing ahead of the June 23-24 meetings between U.S. and Chinese officials in Washington.

At the same time, the official acknowledged the yuan was now "clearly" closer to fair value than it was five to six years ago.

Asked whether the United States might someday join China's new Asian Infrastructure Investment Bank (AIIB), the official said: "That is a decision, if it is taken ... that will be well down the road."

A total of 57 countries, including Group of Seven economies Britain, Germany and France, have joined the AIIB as founding members.

The United States and Japan have so far stayed out of the venture, which is seen as a rival to the U.S.-dominated World Bank and Japan-led Asian Development Bank (ADB), expressing concern about the new bank's governance.

The official said Washington hopes the AIIB can work with the World Bank and ADB to co-finance projects, which would require common ground in terms of governance.