In a speech in central London, he will argue that a Labour government would borrow £166bn more during the next parliament and claim Miliband would be "more dependent on union money in 2015 than any Labour leader before him".
Although the speech is not due to be delivered until 11am, Labour have already dismissed the criticisms as ludicrous. Speaking ahead of the speech, Grayling told Sky News that the Tories were "taking the debate to the Labour party today over the whole issue of their tax and spending plans".
"We've got independent analysis carried out by the Treasury looking at the difference between how we would handle tax and spending and borrowing in the next parliament compared with their plans," he said.
"And what we've been told is that they would spend effectively £166bn more than we would, borrowing money, increasing the debt for every individual taxpayer in this country by £5,500."
He accused Labour of having "a reckless plan that is being driven … by an old-style leftwing Labour ideology".
Challenged on BBC Radio 4's Today programme over the Tories' reliance on City donors and oligarchs, Grayling rejected the criticisms saying that his party's donors would not influence policy.
He also defended a £160,000 donation to the Conservatives from the wife of a former member of Vladimir Putin's government, which she has paid to play tennis with the prime minister David Cameron.
Grayling said the payment from the wife of Lubov Chernukhin was "entirely legitimate".
The government is pushing for tougher sanctions against Russia, and the prime minister has been accused of hypocrisy over the donation.
Michael Dugher, the shadow Cabinet Office minister, said that Grayling's claims were "absolute garbage".
He said: "Chris Grayling seems to have confused the Labour party, who never have and never will link donations to policy, with the Conservative party who have rewarded the few City fat cats, who give them millions of pounds, with tax cuts for millionaires and hedge funds.
"Unlike the Tories, who rely on dodgy dinners and huge donations from hedge funds, the largest section of Labour's funding comes from our members, a fact we're proud of.
"Rather than wasting people's time with these pathetic smears, the Tories should be getting their own house in order," he said.
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