NHS SHETLAND is expected to overspend on primary care by more than £500,000 this financial year as it continues to pay for locum GPs to counter a lack of permanent staff.
Councillor Allison Duncan told Wednesday's integration joint board (IJB) meeting said it was a "horrendous amount of money" to spend.
Repeating his calls to find further financial assistance, the vice chairman said "we have to make a case to the Scottish Government" for extra cash and added that Shetland "does not have to accept" no for an answer.
The IJB - which brings together NHS Shetland and Shetland Islands Council to look after health and social care - is projected to have a deficit of £2.876 million this financial year.
An item on approving proposals to bridge a projected "worst case scenario" funding gap of £1.861 million was heard in private at Wednesday's meeting as the public were excluded.
The IJB has a savings target this financial year of £2.529 million and by the end of June it had secured £668,00 of savings, with a fair chunk of that coming though the closure of Gilbert Bain Hospital's Ronas Ward.
A report on the projected outturn to the end of 2017/18 by chief finance officer Karl Williamson revealed that there is an expected £554,000 overspend on primary care, mainly through locum costs.
There is also an expected overspend in mental health of £131,000, with £87,000 of that attributed to having a consultant locum visit the isles up to the end of the November, and possibly beyond.
William said he is hopeful that the projected funding gap will decrease as the year progresses.
The IJB as a separate entity is required to break even at the end of each year and this is expected to happen with a balancing payment from NHS Shetland's reserves and underspends.
Director of community health and social care Simon Bokor-Ingram told the meeting there could be an "additional cost pressure" coming after Scottish first minister Nicola Sturgeon announced on Tuesday that the government would scrap the one per cent pay rise cap for public sector workers.
He warned that more savings would need to be found to fund any pay increases.
"We've only got the budget we've got," he conceded, suggesting that Sturgeon describing the rises as "affordable" was some way wide of the mark locally.
Speaking about recruiting GPs, NHS Shetland's chief nurse Edna Mary Watson said there was a wider problem with the amount of GPs available nationally.
Bokor-Ingram said deploying advanced nurse practitioners at Lerwick Health Centre and in Brae has been one solution, while he said rural areas like the North Isles need "bespoke solutions" which will need community input.
He added that a recent recruitment drive for GPs in Unst and Yell had been unsuccessful.
A push to find a new nurse for Fair Isle - which received widespread media attention across the UK - also failed to bear fruit.
There are currently vacancies for salaried GPs in Unst, Yell, Bixter, Scalloway and Lerwick.