The official from Netanyahu's office confirmed on condition of anonymity that Education Minister Naftali Bennett and Justice Minister Ayelet Shaked had been fired, without providing further details, AFP reported.
Both are right-wing rivals to Netanyahu and had broken off from his Likud party years earlier.
Their New Right party failed to win enough votes in April 9 elections to clear the threshold to join parliament.
It is not clear if they will run again in the polls set for September 17.
The pair issued a statement saying they were being replaced and thanking the Israeli public, but did not provide details.
Ministers remain in their posts immediately after Israeli elections, until the formation of the next administration.
Netanyahu failed to build a coalition after the April polls and opted instead for parliament to dissolve itself and approve new elections.
Netanyahu has frequently clashed with Bennett, but it was unclear why he chose to dismiss him and Shaked now.
The sackings could also allow Netanyahu to use the vacated ministries for pre-election bargaining.