A new law to stop prisoners waiting days for support on leaving jail has only been used just once in the year since its launch.

The Prisoners (Control of Release) Act came into force on February 1, 2016 and enabled Scottish ministers to bring forward an inmate's release date by up to two days to aid reintegration.

The scheme is aimed at preventing offenders leaving jail on a Friday or before a public holiday and being unable to access vital services such as housing, healthcare and addiction support due to closures.

The Scottish Conservatives have criticised the "shocking under-use" of the new power and are calling on the government to take action.

However, justice secretary Michael Matheson said the law is only one of a range of measures aimed at helping prisoners reintegrate.

Tory shadow justice secretary Douglas Ross said: "This was a welcome provision which everyone agreed would not only help the chances of rehabilitation, but ultimately improve public safety too.

"So it's extremely disappointing to learn it has only been used on a solitary occasion since its launch last year, and we need to know why.

"It's been well-documented that releasing a prisoner on a Friday, or before a public holiday, means it can be difficult to access services.

"That has an obvious knock-on effect, and isn't fair on the individual for whom we should be doing everything to help reintegrate into society.

"I hope the SNP reflects on the shocking under-use of this legislation and works to ensure it can be applied to more prisoners who would benefit from the scheme."

In a letter confirming the scheme has only been used once, Matheson told his Conservative counterpart that it is an "operational matter" for the Scottish Prison Service on behalf of ministers to decide on its use.

Matheson said investment in support officers means many prisoners now have earlier help in planning for their release to ensure they have access to key services when they leave.

He added: "My officials are taking forward discussions with the Scottish Prison Service and other relevant stakeholders to assess how the flexible release provisions can be better applied to meet the needs of people leaving prison in context of the above measures."

A Scottish Government spokesman said: "The Scottish Government introduced these powers to provide greater flexibility to bring forward an individual's release date on any day of the working week by up to two days for the purposes of the effective reintegration back into the community.

"The legislation is only one part of a suite of options that assist reintegration back into our communities.

"The investment by the Scottish Prison Service in throughcare support officers, for example, means that those leaving custody are now supported in planning for their release at a much earlier stage in their sentence in order to ensure that they do have access to these key services after their release."