Christian missionary John Short, 75, originally from South Australia, arrived in Pyongyang on Saturday and was taken from his hotel by local police a day later.
“He went (to North Korea) because it is such a dark and difficult place,” wife Karen Short told AAP from the couple’s home in Hong Kong.
“Being a Christian missionary he wanted to see empathy for the people there.”
Mr Short’s travelling companion was also questioned by police, but was later released.
“They put him on the plane yesterday morning and thought my husband would follow but he didn’t.”
Mr Short’s interrogation is understood to have focused on religious documents.
It is against North Korean law to spread religious material, and interaction between locals and foreigners is also poorly viewed.
“He carried little booklets he’s written himself, that he’s had people translate into the Korean language,” Mrs Short said.
The Department of Foreign Affairs and Trade has told Mrs Short her husband’s consular case is “different and difficult”.
In a statement DFAT confirmed that Australia’s consular interests in North Korea are handled by Swedish authorities.
“We are in close contact with Swedish officials in Pyongyang to seek their assistance in confirming the well-being of Mr Short and to obtain more information,” the statement said.
Shocked by the news of her husband’s detainment, Mrs Short admitted it is not the first time he has visited trouble spots, having travelled though Vietnam and Burma in more tense times in years past.
“It’s not the easy places that need help,” she said.
Mr Short’s detention continued on Monday as former Australian High Court Judge turned United Nations commissioner Michael Kirby, delivered a scathing assessment of human rights in North Korea.
Mrs Short does not believe there is any link between her husband’s interrogation and the growing international concern for rights in the republic.
In December an American 85-year-old Korean War veteran, detained in North Korean for a short time, described his custody as “comfortable”, having been kept in a hotel room and fed traditional food.
But South Korean man, Kenneth Bae, was in April sentenced to 15 years prison in the northern republic after being convicted of planning to overthrow the government.
His imprisonment includes daily hard labour, reports say.
Mrs Short asked Australians to pray for her husband’s safe return.