Incoming Agriculture Secretary Manny Pinol answers questions during a press briefing at DAR on June 8, 2016. Manny Palmero, ABS-CBN News

DAVAO - President-elect Rodrigo Duterte's agriculture chief on Friday slammed the National Irrigation Authority (NIA) for supposedly questioning Duterte's commitment to provide free irrigation for farmers.

In a Facebook post, incoming Agriculture Secretary Manny Piñol criticized a NIA statement that said "Duterte's promise of free irrigation water for the farmers would adversely affect the operations of the agency."

"Anybody in government who does not share President Duterte's vision for the Filipino farmer is free to leave and find another job," Piñol wrote.

Piñol said he was irked by the statement since the issue of free irrigation was already discussed during his transition meeting with the heads of the NIA, National Food Authority, Philippine Coconut Authority, and the Fertilizer and Pesticide Authority.

"In fact, I remember clearly telling NIA Administrator Wencie Padernal to come up with a strategy on how to ensure that the Presidential promise is fulfilled," he said.

"The issue of free irrigation for the Filipino farmers is a presidential commitment and it is non-negotiable," he added.

The soon-to-be agriculture chief said he also received a complaint from DA regional director Jun Alviar after the NIA in Region 2 declined to release irrigation water despite repeated requests from the farmers.

"There is something wrong with the way NIA is being managed right now. Many of its top officials may have forgotten that the reason why there is a NIA is because government would like to produce food for the Filipino people by providing irrigation," Piñol wrote on his social media post.

Piñol earlier said he proposed to the incoming president that the NIA should be brought back under the supervision of the DA.

"It is a vital agency in agriculture dahil hindi pwede ihiwalay ang patubig sa pagtatanim," he told reporters in a press conference here on Thursday.

The incoming agriculture secretary is positive that his proposal will be approved by the 16th president as he was already asked to write a memorandum about the issue.

As for NIA officials who will continue to go against Duterte's irrigation policies, Piñol said: "I will place a big garbage can in front of my office on July 1. You could throw in your resignation letters in that trash can and leave government."