He also said his ambition of holding a second independence referendum in 2028 was realistic, insisting there was “precedent” for another vote if the SNP won an outright majority on 7 May.
Any vote would need to be signed off by the UK government. However, Labour ministers have repeatedly refused to countenance a referendum, and have not set out how an SNP government could democratically secure a vote.
Swinney told the BBC there were “fundamental democratic issues at stake here”.
He added: “If the UK government accepted in 2014 the result of the election of a majority SNP government in 2011 then that should be good enough in this occasion.”
The SNP manifesto includes about £1.4bn in spending plans beyond what the current Scottish government has committed to – including more than £500m to expand childcare provision and more than £200m to subsidise bus travel.
The party said the pledges would be funded by increased tax revenues and extra cash from Westminster, coupled with efficiency savings.
David Phillips, head of devolved and local government finance at the IFS, said the SNP had failed to give a credible explanation, external of how it would pay for its proposals, warning they would likely require “further tax rises or deeper cuts to lower-priority spending”.
The manifesto said that independence would allow the government to build a “fairer and more prosperous” country.
But Phillips warned that while independence could lead to higher economic growth, it would likely add to financial pressures in the short term. He said this is because Scots benefit from more public spending per person than people in the rest of the UK, citing Government Expenditure and Revenue Scotland, external figures.