Chief Constable David Crompton, of South Yorkshire Police, said motorway users and the emergency services would be endangered by the new arrangements.
Changes are planned between junctions 32 and 3 in South Yorkshire.
Robert Goodwill, roads minister, said the plan would "boost the local economy and maintain or improve road safety".
Under the scheme the motorway's hard shoulder would be converted to a permanent traffic lane. Similar schemes on other motorways operate only during particular times of heavy traffic.
Mr Crompton said he had sent a letter outlining his concerns to Mr Goodwill.
"At some point we believe these arrangements... will be a contributory factor in a serious accident or even someone dying", he added.
Mr Crompton said under the scheme the emergency services could take longer to get to the scene of a crash and "the hard shoulder is there for a very good reason".
Mr Goodwill said: "Existing smart motorway schemes have not only improved reliability and eased congestion, but have also improved safety - findings from the M42 pilot scheme showed that accidents more than halved with no fatal accidents in five years.
"After meeting with Meg Munn [Sheffield Heeley MP] and local police we are looking at ways we can further enhance safety, but the chief constable should carefully look at the evidence from existing smart motorway sections, which are already saving lives."
The chief constable said the M1 scheme was not the same as one already in place on the M42 near Birmingham.
"What is proposed here has a lot less control of driver behaviour and it is much harder to regulate the flow of traffic."
The section between Junction 32 (M18) and Junction 35 (A616) carries more than 110,000 vehicles each day and suffers from congestion and delay at peak times, according to the Highways Agency.
Construction is planned to start before 2015.
The agency said the M1 scheme would deliver benefits "at a significantly lower cost than conventional motorway widening".
The cost of the scheme is estimated to be up to Â£133m, it said.
Ms Munn had previously described the plan as "a cheap way to widen the motorway".
Allowing motorists to drive on the hard shoulder of the M1 motorway permanently will cause "a serious accident", a high-ranking police officer has said.