Ms Tong's sister Linzi , who lives in Melbourne, believes Jacqui was the New Zealander referred to by Neil and Sandra Chesterton, who were last week trekking out of Afghanistan with their two sons.
They had told their daughter Gael Murray in an e-mail that one New Zealander had decided to stay.
Linzi Tong said her sister was heading for the Tajik capital, Dushanbe, with some Red Cross aid workers. They had decided against going to Pakistan because of growing anti-Western sentiment.
Linzi Tong was hoping to receive confirmation last night from the MSF London office that Jacqui had crossed the border.
New Zealand Red Cross aid worker Margaret Bryson is now in Geneva after fleeing Kabul.
New Zealand officials are now focusing their attention on the New Zealanders in neighbouring Pakistan, but at least one has no intention of fleeing.
Siobhan Isles, from Wellington, is working for MSF in Peshawar, preparing for the thousands of refugees expected to pour across the north-eastern Afghan border.
The Ministry of Foreign Affairs and Trade has warned New Zealanders to avoid Pakistan because of the expected US military action, but when she heard of the terrorist attacks, 33-year-old Isles rushed to Pakistan from Holland.
"It's quite frightening to be here, but that's part of our job, to do work in front-line areas and areas of conflict where people need the most help."
Ms Isles said the town was increasingly volatile due to anger over Pakistan's pledge to support the United States against Osama bin Laden. MSF workers were ready to leave at any moment.
She is in daily contact via phone and e-mail with her parents in Wellington.
"They are anxious about it, of course. To be honest, I think it's harder for them, because of what they see on the international news. I know I'm fine."
Meanwhile, a New Zealand passport holder is among the 6333 missing, presumed dead, in New York.
American John Lozowsky lived in New Zealand for about 10 years before moving to New York in April 1999.
He worked for the National Archives before joining the Treasury, where he was assistant director of information management from 1990 until 1996.
The Foreign Affairs Ministry confirmed the missing man as Mr Lozowsky, who had dual New Zealand-American citizenship and had been living in New York for the past two years.
Mr Lozowsky was the information technology manager at the Ministry of Health from January 1996 to April 1999.
He was heavily involved in New Zealand's information technology community.
Since leaving New Zealand, he had been working in New York as an IT consultant.
The health ministry has held a private service for staff and some former Treasury colleagues.
His partner has been keeping vigil in their home in Skaneateles village in New York, waiting with his family for any news from rescue workers who are searching the ruins of the World Trade Center.
Last night, she expressed her thanks to his friends and former workmates in Wellington, saying it was "wonderful" to hear about the ministry's service. "I'd just like to say thank you, and it's so nice."
Secretary of Treasury Alan Bollard said Mr Lozowsky had been instrumental in getting Treasury's website up and running in mid-1995, making it one of the first Government departments to have a website.
"We are very saddened by this news and would like to send our condolences to John's family," Dr Bollard said.
Another expatriate New Zealander, lawyer Alan Beaven, 48, has been confirmed dead in the United Airlines Boeing 757 that crashed near Pittsburgh.
His wife, Kimi, has said Mr Beaven would have been one of the first out of his seat to try to overpower the plane's hijackers so it did not crash into a crowded city.
Map: Opposing forces in the war against terror
Afghanistan facts and links
Full coverage: Terror in America