Hun Sen saidthe decision was made at the request of Cambodian Interior Minister Sar Kheng,without giving further details.
It is thefourth Senate election originally scheduled for January 14, 2018.
Founded in1999, the Senate has 61 seats, but only 57 senators will be elected, as two senatorsare appointed by King Norodom Sihamoni and the other two by the parliament'slower house.
In the lastelection held in January 2012, Hun Sen's ruling Cambodian People's Party won 46seats.
Earlier on October 20, the Cambodian Senate adoptedfour amended and supplementary election laws which were ratified by theparliament on October 16.-VNA