Elderly people and those on low incomes are among groups who could suffer after Western Isles Council announced it is considering cutting 84 jobs, a union has warned.

Unison raised concerns the cuts will hit important services for vulnerable groups while also putting local private-sector jobs at risk.

It is claimed, for example, that moving children in residential care into foster care could lead to the loss of 28 posts.

Flora Somerville, Unison branch chairwoman, said: "Cutting jobs has a direct impact on councils' ability to deliver high-quality services to our local communities.

"Cuts to local services have a disproportionate impact on those with low incomes, the elderly, disabled and other vulnerable groups. Good quality services provided by local government must be properly funded."

A reduction in central government funding has forced the authority to propose a raft of cuts and savings to stave off an estimated £14m black hole for the next two years, council leader Angus Campbell said.

The council is poised to slash spending and implement cuts to shore up nearly two thirds of its deficit. But £5m of savings still needs to be identified, a spokesman said.

Even if a list of 29 proposed cuts were agreed, the council would be left with shortfalls of £1.5m in 2016 and £3.6m in 2017.

The local authority has £5.4m of uncommitted funds, which could offset the shortfall in the short term, but it still risks having a £3.6m deficit in two years' time.

Mr Campbell said: "Due to past financial management we are in a more fortunate position than some other local authorities in setting our budget.

"However, having to find this level of savings on top of the savings made over the past few years is challenging to say the least."

The council has a budget of around £111m this year. Controversial proposals to save £264,000 by abolishing the Benbecula to Stornoway air service and a further £322,000 by closing Eoligarry and Iochdar primary schools have now been withdrawn from public consultation.

Proposals to stop the use of all specialist travelling teachers for gym, music and art classes in primary schools is a contentious issue among parents. The plan could save £465,000 over the two years but may result compulsory redundancies, said a report.

Hiking harbour dues by 4.7% or charge for the fishermen's car park in Stornoway is also being considered, although the council report warned the "fishing sector is under pressure from marine protected areas and may see any increased costs as further pressure on a fragile industry".

Meanwhile, closing the council-run Stornoway abattoir would affect the islands’ crofting community and halving the £80,000 funding to the Energy Advisory service risks increasing fuel poverty across the isles, it said.

Other proposals being looked at include upping car park charges in Stornoway town centre and closing the coffee shop in the town's library or tourist facilities at the bus station.

All of these options would likely see further redundancies, the council report found.