The bulk of the savings – some £8.8bn – would come from paying workers living in cheaper areas of the country less than counterparts in places like London and the South East where the cost of living is higher.
Ms Truss’s campaign team did not confirm whether this would include UK Government jobs situated in Scotland when asked by The Scotsman.
Last year the UK Government announced plans to move hundreds of civil servants to Glasgow with plans to open a second Cabinet Office headquarters.
At least 500 officials from the renamed Department for Levelling Up will be relocated by 2024, with senior staff and ministers all now preparing to spend “some time” in Scotland.
The goal was to have Whitehall departments work more closely with Scottish business, with the Cabinet Office stressing the need for decision makers to be “close the people they serve”.
It formed part of the Prime Minister’s plans to “level up” across Britain, as well as show support for the Union.
Ms Truss’s proposals have been met with a furious response from a major civil service union, which vowed to oppose her plans “every step of the way”.
The foreign secretary said: “As prime minister I will run a leaner, more efficient, more focused Whitehall that prioritises the things that really matter to people and is laser-focused on frontline services.
“There is too much bureaucracy and stale group-think in Whitehall. If I make it into Downing Street, I will put an end to that and run a Government that focuses relentlessly on delivering for the British public, and offer value to hard-working taxpayers.
“I have shown in my time in Government that I’m prepared to take on the Whitehall orthodoxy and get things done.
“The British people can trust me to deliver on my promises and tackle the cost of living immediately.”
The Truss campaign argued that because Civil Service pay is negotiated at a national level, no account is taken of the regional cost of living.
By introducing regional boards, civil servants’ pay can be adjusted in line with the actual areas where they work, saving the taxpayer billions, but also ensuring private employers are not “crowded out” by higher public sector wages.
The savings could be enhanced by moving more civil servants out of London.
Around £2bn would be saved by bringing the average Civil Service leave entitlement down from 27 days to the 25 found in the manufacturing and private services sectors.
Scrapping Whitehall diversity officers would save around £12 million a year. Ms Truss’s campaign said there are at least 326 of the roles in Government departments.
Facility time, under which trade union representatives receive paid time off to focus on union work, would be banned – as would allowing the use of grants, offices and equipment – saving up to £137m, the Truss campaign said.
The package of measures set out by Ms Truss are likely to meet fierce resistance from Civil Service unions if she tries to implement them from No 10.
A campaign source said: “Liz is a low-tax, small state Conservative with a distrust of big government. She will shake up Whitehall and take the radical steps required to tackle the waste and inefficiencies that lie at the heart of government.
“She will make sure every single official knows their job about delivering the pledges made in the 2019 manifesto and the things that the public care about.”
Mark Serwotka, general secretary of the PCS union, said: “If Liz Truss is elected, and if she tries to go ahead with these proposals, she’ll face opposition every step of the way.
“Civil servants are not a political tool to be used and abused for one person’s ambition. They are the hard-working people who keep the country running, day in day out, and they deserve respect.”
Deputy Labour leader Angela Rayner condemned Ms Truss’s plans, saying: “This wannabe prime minister is stuck in the past, fighting old battles, and promising a race to the bottom on public sector workers’ pay and rights.
“Her ‘tailored’ pay plans would level down the pay of northerners, worsening the divide which already exists. This out-of-touch Government’s commitment to levelling up is dead.”
The policy commitment from Ms Truss comes as her leadership rival Rishi Sunak insisted he was “radical, but realistic” as he set out plans to slash income tax.
Mr Sunak is under pressure to make inroads into the lead opinion polls suggest Ms Truss enjoys among the Tory members who will decide the next prime minister as postal ballots begin dropping on Conservative doormats.
The former chancellor, who has strongly criticised his rival for promising “morally wrong” tax and spending plans which would increase borrowing, dismissed suggestions his own plan to cut income tax was motivated by the need to gain ground in the election.
Mr Sunak has committed to taking 4p off income tax within seven years if he becomes prime minister, in a last-ditch attempt to win over Tory members before they start receiving their ballots this week.
Cutting the basic rate from 20p in the pound to 16p would amount to a 20 per cent tax reduction – the largest cut to income tax in 30 years.