The Auditor General said today that recruiting the skilled staff needed for Holyrood’s new financial and social security powers and responsibilities will be challenging and setting up a social security agency and delivering the first wave of devolved benefits by summer 2019 will be particularly difficult.

Around 50% of spending will be raised directly in Scotland by 2020 following the Scotland Acts of 2012 and 2016. And a number of new responsibilities – including around £3 billion of annual social security payments – are also being devolved.

The Auditor General’s latest Scotland Acts report warns that it will be challenging to recruit people with the right financial planning, IT and economic skills in time to meet the complex demands of the new powers.

Caroline Gardner also found that the Scottish Government has not clearly estimated the total cost of putting the new powers into practice or how much it will exceed the £200 million contributed by the UK government.

The extra cost will have to be funded from the Scottish budget.

Ms Gardner said: “Putting the Scottish Parliament’s new financial powers and social security responsibilities into action is a huge and highly complex piece of work.

“More detailed workforce analysis and a much more transparent picture around overall costs are needed to ensure the right people and infrastructure are in place in time.

“Good early progress has been made on the government’s social security plans but they are now at a critical point.”

The report also notes that the new powers bring far greater budgetary risks as well as opportunities as a result of the greater emphasis put on the performance of the Scottish economy.

UK’s withdrawal from the European Union adds extra uncertainty, it added.

To manage the risks, the Auditor General’s recommendations include calling on the Scottish Government to agree the governance and organisational arrangements of the new Scottish Exchequer.

Social security minister Jeane Freeman said she was “confident” that plans for the agency were on track.

She said: “We are confident that we are on track against our plans. However, as highlighted by Audit Scotland, it is crucial that we have clarity and confirmation - and that we understand what the DWP’s detailed plans are.

“We cannot deliver this in isolation and we need to know that the DWP is able to match our pace.

“We recognise the significant amount of work still to be done as we continue the programme to transfer powers, bring forward legislation and build the infrastructure we need.

“We are confident that we have robust plans in place and a full understanding of our overarching costs and are on track to deliver benefits to Scotland’s people.”