A Tasmanian Supreme Court judge has rejected a proposal to sell off seven heritage-style cottages that were built to accommodate spinsters in the state's northern midlands.

Sarah Louisa Noake died in 1910, leaving instructions for cottages to be built on her land at Longford, which were then to be rented out to "spinsters in poor circumstances".

Her will stated that if such spinsters could not be found, the cottages could be rented out generally, with the income to go to the Queen Victoria Hospital for Women in Launceston.

The term "spinster" generally refers to a woman who is unmarried past child-bearing age.

In 2013, Tasmanian Perpetual Trustees Limited applied to the Supreme Court to vary Miss Noake's trust, saying its original purposes had become impossible to carry out.

The trustees argued that real estate agents were finding it increasingly difficult to find spinsters to rent the seven cottages to.

Tasmanian Perpetual Trustees' Phillip Wheeldon said that difficulty was further exacerbated by the cottages' location in Longford, which had a limited population of spinsters.

Further, the Queen Victoria Hospital closed in 1995, and was incorporated into the Launceston General Hospital as the Queen Victoria Maternity Unit.

Tasmanian Perpetual Trustees' applied for approval to sell the property, so the proceeds could be invested in a share portfolio to benefit that maternity unit.

Scheme to donate money to maternity unit, cottages can't be sold

In her judgement, Supreme Court Judge Helen Wood said she would not allow the cottages to be sold as it would violate the spirit of Miss Noake's will.

But she ruled the trustee would be able to distribute income to the Queen Victoria Maternity Unit.

Justice Wood said she was proceeding on the factual basis that spinsters in poor circumstances were not seeking to rent the cottages.

"It is unsurprising that, due to historical reasons, there is reduced demand for spinsters," she said.

"In today's society, there would be far fewer women who would identify as spinsters.

"The term lacks currency and is not consonant with community attitudes."

But Justice Wood said while the term had fallen out of usage, that did not mean there was not a category of women who qualified as spinsters in poor circumstances.

Justice Wood found a share portfolio would sever any possibility of any assistance to spinsters in the future, and that was not in accordance with Miss Noake's will.

She also noted the proposed scheme would spell an end to the Noake family legacy in the Longford area.

But Justice Wood found that because the Queen Victoria Hospital for Women in Launceston no longer existed, the trustee had not been able to distribute surplus income as directed under the will.

She said she was satisfied that a limited variation to the trust should be approved, so that surplus rental income could now be directed to the Queen Victoria Maternity Unit at the LGH, rather than the now non-existent Queen Victoria Hospital for Women.

Justice Wood did not approve the other aspects of the proposed scheme.

"The circumstances do not justify the wholesale scheme proposed ... the difficulty with spinsters not renting cottages is provided for in the terms of the gift and could not amount to impossibility or impracticability in carrying out the original purpose," she said.