Getting the deal on a new funding framework for Scotland correct is more important than reaching an agreement with the UK Government by the end of the autumn, John Swinney has said.

While the UK Government is keen the new powers in its Scotland Bill should be in place quickly, the Scottish Deputy First Minister stressed the fiscal framework linked to that must be right.

Talks are currently taking place between the Scottish and UK governments over the framework, with three meetings having been held already and another to take place later this month.

Mr Swinney told MSPs at Holyrood the aim was for these discussions to be completed by the end of autumn but added: "Let me be clear. The determining factor for me is getting the framework correct rather than observing a particular timescale on that process."

He made the comments after Scottish Secretary David Mundell revealed he wanted Holyrood's new income tax powers commence in 2017 - earlier than had been expected.

The Conservative said: "The final date for the transfer will be agreed between both of Scotland's governments as part of the fiscal framework negotiations, which are ongoing. But we think 2017 is an achievable and desirable time for these new powers to take effect."

The Scotland Bill, which was brought forward after the Smith Commission's review of devolution in the wake of the independence referendum, is currently going through Westminster.

Mr Swinney stressed the fiscal framework that accompanies the Bill was an "integral part" of further devolution to Scotland.

Both Mr Swinney and First Minister Nicola Sturgeon have warned they will recommended Holyrood does not grant its consent to the legislation if they deem the framework to be unfair.

The Deputy First Minister said: "We see the fiscal framework and the Bill as one and the same thing - there is no point in having the powers if we do not have the fiscal framework that allows us to exercise the powers without prejudice to the interests of Scotland."

He told MSPs he would not sign up to any adjustment of the block grant from Westminster to Scotland that "is not fair".

Mr Swinney said: "The baseline for Scottish public expenditure must continue to be set through the Barnett formula, that is what was promised in 'the Vow'.

"There will inevitably be an adjustment then applied to the block grant to account for our new tax and spending powers.

"Any adjustment mechanism that simply seeks to reduce Scotland's funding year after year irrespective of the policies we pursue will not be acceptable to this government."

Opposition MSPs criticised the "lack of transparency" surrounding the discussions between the UK and Scottish governments about the fiscal framework.

Labour MSP Jackie Baillie said: "These discussions currently are shrouded in complete mystery.

"I am genuinely at a loss to understand why the Cabinet Secretary is unable or perhaps even unwilling to share with this Parliament, who are allies to him in this project, and indeed with the people of Scotland, precisely what is going on.

"It makes it quite difficult for us to engage in a meaningful conversational dialogue if both governments are not telling us about their proceedings."

Conservative MSP Gavin Brown said: "I can't help but think that there is some possibility that we could get a bit more information than we currently get so that Parliament and the Finance Committee in particular have a slightly clearer idea of where we are going.

"I think it's important for the Scottish Government to lay out some of its stall because it has said publicly ... quite clearly and quite loudly that they are going to block the Scotland Bill or at least recommend the Scotland Bill be blocked unless the fiscal framework is fair."