Those close to Christian singer Carman are asking fans to pray as he battles several health conditions following surgery last week.

Last year Carman announced that the cancer he was diagnosed with in 2013 had returned. On January 19, his 65th birthday, he wrote that he was in hospital and doctors were working to improve his condition.

He underwent surgery last week, and his recovery became life-threatening.

"Today I'm in the hospital, I was getting a hiatal hernia removed yesterday," his birthday post reads, calling it a "near-fatal birthday."

"For some reason, no one knows why, my blood pressure dropped to 66/43 and and kept falling. It's usually 135/89. I woke up from the anesthesia and saw nine doctors and nurses standing around my bed buzzing about, deeply concerned. They worked for hours to get it going the other way."

Since then, he has developed pneumonia and began to experience organ failure.

"Recovery was not going well and his temperature continued to rise," a post on his Facebook page on January 25, says.

"They discovered it was caused by internal bleeding and had to do another surgery last night to fix that. His temperature has gone down but now he has pneumonia and his kidneys and liver are not working fully. He needs a touch from the Lord right now!"

There has been no update in the following day.