Two more people would still be missing, according to local media.
The accident occurred shortly before 4 p.m. local time at an altitude of almost 3,000 meters over the Rutor glacier located in La Thuile Valley in northwest Valle d'Aosta region at the border with France.
Alpine rescue teams were the first to reach the scene, while two helicopters with Civil Protection technicians and one doctor on board were dispatched soon after, the national Mountain Rescue Team said on Twitter.
Five bodies were recovered up to about 7 p.m. local time, when search activities had to be suspended.
Two people were rescued and flown to Parini hospital in regional capital Aosta in critical conditions, a spokesperson for the Civil Protection told Xinhua.
They were both hospitalized in intensive care.
While the nationality of the victims was not disclosed, as of Friday, the Mountain Rescue Team specified on Twitter the two wounded were a French and a Swiss.
Two more people -- both French nationals -- are would be still missing, according to Ansa news agency.
Authorities did not officially confirm it on Friday, but the Civil Protection agency and the Mountain Rescue Service stated that their search and rescue activities would resume at dawn on Saturday.
The Civil Protection spokesperson also acknowledged authorities could not rule out that more people were involved in the crash, apart from the five victims and two injured so far accounted.
The two aircraft involved in the crash were a San Jodel D.140E plane and a helicopter AS350, according to Italy's National Flight Safety Agency (ANSV).
The plane had taken off from the French aerodrome of Megeve on the other side of the border, state-run Rai News 24 TV reported.
The helicopter belongs to a private company based in the Italian city of Courmayeur, which provides heli-skiing service and panoramic flights, according to their website.
Prosecutors in Aosta opened a criminal investigation against unknown persons on charges of involuntary manslaughter and culpable disaster.
The ANSV will also open an inquiry, and send an investigative team to the accident site, the agency said in a statement.
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