Scottish nurseries have to absorb the biggest funding shortfall in the UK, according to a new survey.

The study by the National Day Nurseries Association (NDNA) warns that an average funding gap of £40,000 per nursery threatens to limit the ability to offer more free childcare hours.

Across Scotland, 86% of private and third sector nurseries deliver free places for three and four-year-olds.

The SNP plans to increase funded hours from 600 to 1140 per year by 2020.

Nurseries which responded to the survey said that they were unlikely or unsure they would offer additional free hours, however.

They are paid an average of £3.56 per hour by local authorities for a free place for three and four-year-olds, but this falls short of their costs by £1,128 per child per year.

The average nursery offering 35 places has to absorb losses of £39,480 every year.

NDNA Scotland's chief executive Purnima Tanuku said: "This enormous shortfall is a huge burden on private and third sector nurseries.

"They have no choice but to try to absorb these costs themselves or pass them onto parents by increasing fees for additional hours or for younger children.

"Their main concern is that if free early learning and childcare is expanded, far fewer parents will need any additional hours, so they will struggle to make up this shortfall."

Almost half of the nurseries which responded expected only to break even, with 11% expecting a loss.

Around half of providers would be likely to extend their funded hours and 22% were unlikely or very unlikely to increase the amount of funded places they offer.

Ms Tanuku added: "We know that parents can't always send their children to their choice of provider because local authorities are limiting funded places at private and third sector nurseries. This rationing is undermining families' choice."

She called on the next Scottish Government to ensure all childcare providers are able to offer funded hours on a "level footing".