Miller has probably suffered a broken arm and leg, Polish Television TVP said on Thursday.
Ten of the 12 people on board the Soviet-built MI-8 were injured in the incident, which happened as Miller returned from a trip to southern Poland, several sources said.
One of the prime minister's bodyguards was seriously injured, Polish public television reported.
The M-18 helicopter was said to have suffered technical problems.
Witnesses said Miller had been taken directly to the government hospital in Warsaw following the accident.
Miller's political adviser Tadeusz Iwinski declined either to confirm or deny that Miller had been injured.
TVP reported that the helicopter was more than 30 years old.