There are more than 300 prisoners on home detention curfew

Ministers said the move would take pressure off Scotland's high prison population, but was narrowly rejected by the parliament's justice committee.

MSPs cited a lack of provision to review the change at a later date.

Ministers will now make a second attempt to get the measures through a meeting of the full parliament.

Justice Secretary Kenny MacAskill branded the committee's decision "appalling", and accused rivals of playing politics.

Labour and Tory MSPs joined forces to reject the government's plan to increase the amount of time prisoners can spend under home detention curfew from four-and-a-half months to six months.

'Significant' problems

Mr MacAskill said he would review the extension but members of the committee said the pledge did not go far enough.

They had demanded a specific "sunset clause" which would have ended the order when the new prison at Addiewell in West Lothian was up-and-running.

Committee convener, the Tory MSP Bill Aitken, used his casting vote to turn down the plans after a tied vote.

Speaking afterwards, Mr MacAskill said: "I'm appalled. I think Labour and the Tories are playing politics with our prisons."

The justice secretary said action was being taken to address Scotland's "significant" prison overcrowding problems, inherited by the previous administration.

According to the latest official figures, there are about 330 prisoners on home detention curfew, which applies to short-term prisoners on sentences of between three months and four years.

The extension would have seen that rise by between 50 and 120.