The $1 million - promised by then Labour leader Andrew Little at a public meeting in Oamaru in July - would take funds raised to $6.1 million, Maniototo Health Services Ltd (MHSL) manager Geoff Foster said.
The project required $6 million to proceed, and the $1 million was the last amount needed, Mr Foster said.
He said MHSL chairman Stuart Paterson had written to the new Minister of Health, David Clark, and hoped the $1 million would still be forthcoming from the new Labour-led Government.
Mr Clark's office had acknowledged receipt of the letter, but had not yet responded, and hospital leaders appreciated the new ministers would have ``a lot to work through'' with the new Government, Mr Foster said.
He said MHSL was ``keen to know'' as soon as possible if the $1 million was confirmed, as final costings and designs were being done.
Hospital leaders had already increased the scope of the hospital rebuild earlier this year - from $5.5 million to $6 million - to allow larger bedrooms to be built in the facility.
This was because they wanted the ``best possible facility'', and were confident of raising enough money for the rebuild.
Of the $5.1 million so far raised, $2 million has come from hospital reserves, $2 million from the Central Otago District Council, to be either paid back by Maniototo ratepayers or funded through Maniototo land sales, and $1.1 million from grants and Maniototo fundraising.
Mr Foster said he ``continued to be vastly impressed'' by the strength of the Maniototo community. Not only had they made a significant financial contribution, their passion and enthusiasm had greatly contributed to the motivation and momentum of all involved with the project.
However, hospital leaders were still disappointed the previous government had not provided any funding, Mr Foster said.
``Obviously dealing with the [National] government has been disappointing for us, but I've always been confident we'd get there one way or another, just from that total commitment from the community to make it [the rebuild] happen.''
The rebuild was scheduled to begin in the first quarter of 2018, and the foundations needed to be down before winter, Mr Foster said.
Mr Clark did not respond to a request for comment.
