Australia is seeking the whereabouts of John Short, an elderly Christian missionary recently imprisoned in North Korea.
His family said Short, 75, was arrested Sunday in Pyongyang.
Australia officials said they've been trying to determine where Short is being held and what his condition is.
"We have made attempts through the Swedish counterparts to establish how he is, where he is and I'm waiting for reports on that so I am rather limited by what I can inform you," Australian Foreign Minister Julie Bishop told a news conference in the Philippine capital, Manila.
So far, no answers have been forthcoming from North Korea.
Short's wife told the Associated Press he might have been arrested for carrying Korean-language Christian pamphlets into North Korea.
But Jeff King, president of International Christian Concern, said Short's arrest may have more to do with a recent U.N. report accusing North Korea of committing crimes against humanity.
"The man who headed up the commission for the U.N. was an Australian. He's an Australian judge," King noted. "So, we think the angle is -- this is punishment and it's a bargaining chip. That's conjecture, but it certainly looks interesting and it looks like an overbearing response to a small offense."
***Read more of King's comments on Gary Lane's blog, The Global Lane.