Foreign investors are showing interest in buying US shale assets even as domestic players are finding it more difficult to access the capital they need to secure deals.

"North America is open for business, there's just a dearth of capital for upstream right now," Banpu Kalnin Ventures (BKV) chief executive Chris Kalnin said.

"So, it creates this unique buying opportunity."

BKV, which is backed by Thai utility Banpu, closed its acquisition of Devon Energy's assets in the gassy Barnett shale of Texas last week.