"She was sleeping, minding her own business," Mr Franzoi said.
"My son told me they woke up hearing gun fire. The lady who was with them, the group, was telling everyone to get on the floor but he fell asleep.
"Then someone woke him up saying 'your mum needs to talk to you'. So he went into her room and there she was with a bullet in her leg."
Mrs Franzoi was in a stable condition but was transferred to Cairns because of the lack of medical equipment available in Port Moresby.
She was preparing for surgery today.
Mr Franzoi said his wife contacted him to break the news.
She told him: "Don't panic but there has been an accident...I've been shot."
Mr Fanzoi said at first he thought she was joking.
"I said to her, 'you better not be joking because if you are I will shoot you myself'."
He soon realised that she was serious but she quickly calmed his nerves by telling him she was okay.
"She was sleeping on her side and heard 'get on the floor' when she said it was like someone put a red hot point of metal and put it right into her leg.
"She realised she was shot and rolled on to the floor."
The couple's son, Luke, arrived home today.
Mr Franzoi, also a volunteer ambulance officer and volunteer fireman at Waihi Beach, said family and friends were in disbelief.
The couple have lived at Waihi Beach for three years after emigrating from South Africa, where they worked as paramedics.
"There are so many times that I could have been shot over there (South Africa) and I wasn't - and then this happens to her...."
The Ministry of Foreign Affairs and Trade (MFAT) said it had been informed of Mrs Franzoi's situation.
"We are aware of the reports that a New Zealand woman has been treated in hospital for a gunshot wound," a spokeswoman said.
"The New Zealander was in PNG as part of a medical team providing assistance in the villages.
"The New Zealand High Commission in Port Moresby have extended consular support."
Mrs Franzoi had been working with Youth With A Mission (YWAM) in PNG. The Christian group today said it was "very sad" to confirm one of its volunteers had been injured.
"Cathy Franzoi, of New Zealand, was hit in the leg by a stray bullet while staying in Port Moresby," it said in a statement.
"The incident occurred after she had completed a project serving on our medical ship helping local people in Papua New Guinea's Gulf Province with medical training and community development needs, while awaiting her return flight to New Zealand.
"Our thoughts are very much with Cathy and her family, and our priority remains to do whatever we are able to speed her recovery."
The non-profit organisation had an "excellent safety record", it said.
"This is the first incident of its kind that one of our volunteers has been involved in over 22 years facilitating short term volunteering trips overseas.
"We are fully cooperating with local authorities and will be conducting our own thorough assessment of the circumstances surrounding the incident to understand if there is anything we can do to improve the safety for our volunteers on future visits."
Mrs Franzoi had travelled to PNG -- where she had been for two weeks -- with members of her church, Waihi Baptist Church, said community pastor Alan Scott.
"Our immediate concern was for the well-being of every member of that team," Mr Scott, who was also on the trip and returned late last night, said in a statement.
"As a consequence, Cathy required medical assistance and along with a support person was evacuated from PNG yesterday afternoon and is currently receiving treatment in Australia. The remainder of the team returned to family in New Zealand as scheduled last night.
"Each member of the team has had a memorable time in PNG and is determined that a single event will not overshadow the amazing experience and all are keen to return on another occasion."
