Manila: The office of Philippine President Rodrigo Duterte has "deep concern" about a congressional Commission on Appointments (CA) decision to reject his choice of environment minister, but will respect the democratic process, his spokesman said on Wednesday.

"She has contributed a lot of meaningful insights into the environment and the Philippine environmental situation, and it is of course with deep concern that the CA has seen it fit to reject her appointment," presidential spokesman Ernesto Abella told reporters.

"On the other hand, it's a democratic process and we respect their decision... We just have to accept what the CA has decided." Abella was asked if it was possible Lopez would be given another post in the Duterte administration and responded: "That's a possibility but we don't know yet".