Tens of thousands of nurses and ambulance staff in England are set to walk out in what is expected to be the biggest strike in NHS history.
Mr Shapps said the Royal College of Nursing (RCN) has "very responsibly" told the NHS about where they will be striking and therefore enabled emergency cover to be put in place, but claimed ambulance unions have not provided such information.
His comments came as he sought to justify controversial anti-strike legislation currently making its way through Parliament.
The Strikes (Minimum Service Levels) Bill seeks to ensure there are minimum working standards during strike days across six sectors, including health and transport.
Mr Shapps, asked if the industrial action will put lives at risk, told Sky’s Sophy Ridge On Sunday programme: "I am concerned that it does, if you have a situation which has been happening so far where you don’t have co-operation between the back-up services - typically the Army - and the people who are striking.
"We have seen the situation where the Royal College of Nursing very responsibly before the strikes told the NHS 'This is where we are going to be striking' and they are able to put the emergency cover in place.
"Unfortunately, we have been seeing a situation with the ambulance unions where they refuse to provide that information. That leaves the Army, who are driving the back-ups here, in a very difficult position - a postcode lottery when it comes to having a heart attack or a stroke when there is a strike on."
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Unison union head of health Sara Gorton, during strikes last month, said all the services involved had emergency cover which, "as a rule of thumb", saw all life-threatening incidents - also known as category 1 calls - responded to.
Category 2 calls, which can include heart attacks and strokes, would be assessed and if there was "risk to life and limb" ambulance staff would leave picket lines to respond.
Ahead of Monday’s strike, nursing leaders have issued a direct appeal to Rishi Sunak to intervene in their pay dispute.
In a letter to the prime minister, the Royal College of Nursing (RCN) general secretary Pat Cullen said that a "meaningful" pay offer from the government could still avert strike action.
She drew a comparison with his swift action sacking Conservative Party chairman Nadhim Zahawi after he was found to have breached the ministerial code in relation to his tax affairs.
"As shown by last weekend’s fast-paced changes in Cabinet, big decisions can be made by you at any point in the week in the interests of good government," she wrote.
"I am urging you to use this weekend to reset your government in the eyes of the public and demonstrate it is on the side of the hardworking, decent taxpayer.
"There could be no simpler way to demonstrate this commitment than bringing the nurse strike to a swift close."
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Nurses are due to strike again on Tuesday while ambulance crews and call handlers will return to the picket lines on Friday.
In contrast, the RCN and other unions have called off similar action in Wales after receiving a new pay offer from the Welsh government.
With negotiations also continuing in Scotland, Ms Cullen warned Mr Sunak that his government was becoming "increasingly isolated".
"As a result, the strike action for England next week remains, with tens of thousands of individuals losing wages to ensure you hear their voice. It must not be in vain," she said.
"It will be the biggest day of industrial action in the 75-year history of the NHS.
"Nursing staff find that a sobering realisation of how far they have been pushed to protect patient care and secure some respect for the nursing profession."