Brussels will "start to set the rules for the NHS" as part of a move towards deeper integration that will kick in if the UK votes Remain, Chris Grayling will warn.
The pro-Brexit Cabinet minister will claim major reform plans are being kept deliberately under wraps during the campaign but will go "full steam ahead" if Britain opts to stay in on June 23.
"If we vote to remain in the EU then it would be EU rules that would determine our minimum wage, EU rules that would say how our pensions work," he will say in a speech in London.
"It would be EU rules to govern our skills system and even EU rules that would tell us how health services should work."
Pro-EU campaigners were right to promise reform, he will say, "but the inevitable reform that is coming our way is very different to what they are claiming".
Mr Grayling will reject rivals' claims that Brexit campaigners would seek to weaken social protections once the UK was no longer bound by Brussels rules.
"Let me make clear that I do not want to see social rights and protections diminished if we vote to leave the EU," he will say.
"The point, however, is whether it is for the EU or for the people of the United Kingdom to control our rights and protections."
Labour's campaign has focused heavily on Brussels' role in reinforcing workers' rights, accusing Tories of wanting to water them down.
"We have a new list of EU social policies which will deepen integration across the eurozone. But these will be EU laws passed in the normal way," he will say.
"There is no other method of doing so right now. And we have no opt out from them.
"Many of these measures will be things we already do well; some may be measures we would want in the UK. The point is that it should be up to us to control what happens to the NHS, to workers' rights and to social protection and control over these areas should not lie with Brussels.
"So when there are new EU rules on pensions, skills and health, they will apply to us too. It means the EU starting to set the rules for our NHS. With no opt-out. And millions more people able to access our free at the point of delivery service as countries like Albania, Serbia and then Turkey join the EU.
"And this is why we are not at all exempt from Ever Closer Union. Because the nuts and bolts of integration will come from new EU laws passed under the terms of the Lisbon Treaty."
Other plans will be kept quiet until after the referendum, he will say.
"We know the (European) Commission is on its best behaviour right now. Everyone in Brussels is under strict instructions not to rock the boat. Frankly I am surprised that they have even started the consultation on the Social Pillar.
"But the decision to delay anything controversial in Brussels until after our referendum is an open secret there. Legislation is being held back. The budget is being held back. The EU institutions are in lock down until the British decision is done and dusted.
"If we vote to remain, the plans move full steam ahead."
Michael Gove and Boris Johnson, meanwhile, identified where they would seek to spend some of the cash Vote Leave says would be saved by quitting the EU - on cutting VAT from fuel bills.
The campaign has made the ability to boost NHS spending the centrepiece of its pitch to voters.
But in an article for The Sun, the senior Tories - and Vote Leave chairwoman, Labour's Gisela Stuart - said some could be used to scrap the tax imposed by a Conservative government in 1993.
The least wealthy are hit particularly hard," they wrote.
"The poorest households spend three times more of their income on household energy bills than the richest households spend. As long as we are in the EU, we are not allowed to cut this tax.
"When we Vote Leave, we will be able to scrap this unfair and damaging tax. It isn't right that unelected bureaucrats in Brussels impose taxes on the poorest and elected British politicians can do nothing. We'll also take back control of the VAT on fuel charged to motorists."