Ms Swannell said the offer had moved her to tears.
"We're really excited. We just connected with the right people at the right time. By the end of this year, we're going to have your shelter - I don't know what that looks like, but we will."
The shelter would act as a first port of call for people who found themselves sleeping rough. It would be a 24-hour facility and the Swannells would help guests to liaise with other agencies and find longer-term accommodation. She envisaged it as a "non-judgmental place, for men, women and families".
However, she needed to find land for the relocation of the building in the next couple of months, as well as raise the funds for the relocation.
"We want to find a permanent place for it between Napier and Hastings - it's supposed to be a Hawke's Bay shelter."
They had received relocation quotes of between $80,000 and $100,000. She was asking anyone to come forward who had land to donate or wanted to contribute to the cost of the move.
Hastings Mayor Lawrence Yule welcomed the news of Property Brokers' offer, and said the Swannell family was doing "wonderful work".
"I encourage anybody or any group that wants to help homeless people. In relative terms, the region doesn't have many [homeless], but the people who are homeless are in significant need."
Asked if Hastings District Council would be open to donating land for the shelter, Mr Yule said he would be "open to having a conversation about that".
Ikaroa-Rawhiti Labour MP Meka Whaitiri said Property Brokers should be commended: "One emergency house is better than nothing."
Despite Hawke's Bay being the fifth largest metropolitan area in the country, there was nowhere for those most in need to go, she said. The nearest emergency housing to Napier was Palmerston North, more than two hours away.
She said the current level of homelessness was unacceptable in the 21st century.
Nine out of 10 people who came to her electorate office needed help with housing.
It was the Government's responsibility to provide affordable, warm housing to those in need, she said.
However, the provision of emergency housing was "random, patchy and far below what is needed".
For more information, search the key words "Limitless Hope" on Facebook. To donate funds for the building's relocation, visit: givealittle.co.nz/limitlesshope.