Wellington's Wayan Rosie is having to face the reality he may have to leave a Vietnamese family homeless after tearing down their home but not having enough money to rebuild.

An impoverished Vietnamese family is homeless after a well-meaning Wellington man tore down their home but could not build it again.

Wayan Rosie, a regular visit to Vietnam, was so touched by the hard-luck story of a local family when he visited in 2013 he vowed to return to build them a new home.

He returned to New Zealand and began fundraising but fell short of the $15,000 target he set.

Supplied A Vietnamese family's home has been torn down to create retaining walls of the new home.

DONATE: Givealittle page for Lo Thi Lem's family home

He added about $2000 to the account himself and three weeks ago flew to Vietnam to get to work - starting with demolishing the existing home - but unexpected costs meant he used up the money and the house was far from complete.

Meanwhile, the family is having to live with neighbours and Rosie has had to come to terms with the fact he may have to return to New Zealand leaving them without a home.

Supplied Vietnamese tour guide and breadwinner for her family Lo Thi Lem.

"I've actually really made a bit of a mistake not planning this project out properly," he admitted.

Before leaving New Zealand, Rosie, had been in touch with the family about the best time to build the house.

He was assured the $6000 he had raised was enough.

Supplied Lo Thi Lem's home in Vietnam before it was torn down.

Problems were compounded because they needed to build a large retaining wall to bring the section up to a "workable" level then fill it in.

"[It] has been an expensive exercise, but just had to be done before building started."

He now hoped to, at least, get the roof on the house - but that would still leave it without walls, doors, bathroom or kitchen, with the rainy season coming.

"'I'm pretty stressed out and worried that I will leave the family without a home now. I've already put in all the money I personally can ... I don't want to leave them homeless."

He pledged to return next year to complete the job if he could raise the money.

But he hoped to raise enough money now to keep building so the family could move back in at the end of June.

He also planned to continue to help other locals in the area and was already talking to an architect about simple, cheap ways to build new homes out of the local materials.

"This learning curve is great though. I've learn so much about how the building industry works here out in the rural areas."

Rosie originally met the family he was trying to help when trekking through the region in 2013.

Their 19-year-old guide Lo Thi Lem, took them to her home, which was "the worst home in the village", below road level, in a swamp, and covered in asbestos.

Her father died when Lem was 10, and her mother had a bad fall four years later, breaking her leg and leaving her permanently crippled.

From the age of 14, Lem had been taking care of all household responsibilities, as well as being the breadwinner and looking after her two younger siblings.