"When we first got to him he was just breathing. I don't know if it was all the dried blood in his throat or not," said Ms Martin.
"Seb said he saw three massive bruises and his eyes were only partially open."
The couple, who do not have cellphones, went to the police station to raise the alarm, then returned to wait with the man. Mr Graham covered him with a jersey.
As ambulance crews arrived the man stopped breathing. He was taken to Wairarapa Hospital before being airlifted to Wellington. Ms Martin said it was a relief to hear the man is making a recovery, although she was still a "bit shaken up".
Detective Senior Sergeant Sean Hansen said the investigation was still progressing and police were yet to determine how the man was injured.
"We're aware there's a couple of teenagers that saw him lying on the footpath ... they believed he was asleep," he said. "We don't believe they're involved."
Although police have not named the injured man, they know his identity and described him as caucasian, aged 40, clean shaven with brown hair.
He was wearing a black bomber-style jacket, dark blue jeans and black boots.
A hospital spokesperson said the man was in a stable condition and was moved from the intensive care unit into a general ward yesterday.
Mr Hansen said anybody who saw the man in the CBD after 1am or anyone who was in Essex St between 1-6am on Saturday, and who may have noticed anyone or anything suspicious, should contact police.
