The UK Government's decision to extend its work programme contracts undermines the good faith of the Smith Commission process on further devolution, the Deputy First Minister has said.

The commission recommended that the work programme, which helps jobseekers find and keep employment, should be transferred from Westminster to Holyrood when the current commercial arrangements expire.

The Scottish Government said this should mean the transfer taking place in March 2016, but the UK Government has extended the contract by a year.

Scottish Skills Secretary Roseanna Cunningham accused the Westminster Government of "breath-taking arrogance", and wrote to UK Work and Pensions Secretary Iain Duncan Smith to complain.

The Scottish Council for Voluntary Organisations (SCVO) said it was "utterly appalled" by the move to extend the contract.

Scottish Secretary Alistair Carmichael said the decision was made in August, before the Smith Commission was set up.

Deputy First Minister John Swinney, giving evidence to Holyrood's Devolution Committee, said Ms Cunningham's remarks were "understandable and appropriate".

He said: "The Smith Commission recommended that on the completion of the work programme contracts, these should be devolved to the Scottish Parliament and that's in the spring of 2016, and we're now being advised, without our consent, that that's been delayed a year in a process which is not yet complete.

"What we get to in all of this analysis is the whole question of good faith. We need to get on in good faith and one of the things which I think undermines that good faith is seeing the goalposts being moved on an important issue the Smith Commission has judged upon."

But earlier, the committee heard from Mr Carmichael, who said: "First of all, I think it is important to say that this was a decision taken in August, so some of the breathless commentary about this being 'a dreadful decision that was designed to thwart the will of the Smith Commission' is not justified because, frankly, this decision was taken long before the Smith Commission was even set up."

Lucy McTernan, deputy chief executive of SCVO, said: "We are utterly appalled by the UK Government's move to extend its work programme contracts when it was agreed by the Smith Commission that it would transfer to the Scottish Parliament as soon as current contracts expired.

"But our disappointment doesn't lie so much in the almost immediate failure to keep to the agreement as in the fact that it's impossible to justify why such a broken and failing system would ever be continued.

"We're completely dismayed by this delay in ridding Scotland of this exploitative, punitive and under-performing programme."

SNP MSP Linda Fabiani, a member of the Devolution Committee, said that the sooner the programme is devolved, the sooner it can be "put right".

"Quite why the UK Government thinks it is acceptable to completely ignore the Smith Commission proposals and press ahead with its failed scheme is baffling," she said.

A spokesman for the Department for Work and Pensions said: "Unemployment in Scotland fell by 38,000 over the last year and our priority is to ensure as many people are helped into work as possible while fulfilling our commitment to the Smith Commission's proposals on devolution.

"Maintaining continuity of support is important. That is why we are allowing time for the powers to be devolved and for the Scottish Government to build its new programme to make sure long-term unemployed people get the help and support they need to find a job and have the security of a regular wage."

First Minister Nicola Sturgeon met with Mr Carmichael today to discuss the issue.

She said: "I stressed the need to make sure that the UK Government signs no new Work Programme contracts for Scotland as these powers are to be devolved under the Smith Commission recommendations.

"It would not be fair or right that Scotland is tied into this programme longer than it needs to be. Mr Carmichael has pledged to speak to the Department of Work and Pensions on the issue, and they should now rethink their plans.

"Westminster now needs to act to make sure plans for the transfer of the powers recommended for devolution by the Smith Commission are taken forward as soon as possible."

The politicians also discussed extending the franchise to 16 and 17-year-olds for the next Scottish Parliament elections in 2016 after recommendations in the Smith Commission.