Malacanang urged on Tuesday Vice President Leni Robredo to accept the challenge of President Rodrigo Duterte to be the anti-drug czar "to show her mettle" and to help the government.

Otherwise, if she would decline the offer, it means that the government's war on drugs for the past three years was not a failure contrary to her claim, Presidential Spokesperson Salvador Panelo said in a press briefing.

"The ball is in her court. But if I were in her place, I would accept because this is a rare opportunity for a critic who would be given an opportunity to show her mettle and at the same time helping the government," he said.

"As we have repeatedly said, you cannot just keep on criticizing the government, you have to support it; you have to offer your own talent and expertise in solving the problems of the land. So this is one rare opportunity," said Panelo, also chief presidential legal counsel.

On Monday, Duterte dared Robredo to be his anti-drug czar for six months. This was after the vice president branded the government's war on drugs a failure and called the administration to reassess it.

Panelo said whether Duterte's offer was "out of peeve or of serious matter," Robredo must consider it.

Robredo has said many people have been killed in the drug campaign and yet the number of drug users continue to increase.

"If she (Robredo) declines, it only shows that it is not true that this war on drugs is a failure and that there should be more or other measures to be undertaken to stop it," said Panelo, who sent a text message to Robredo, asking if she would accept the challenge.

"I said?this is in Bicol, because we’re both Bicolano. Translated: 'There is an offer for you from the President to be the drug czar for six months. Will you accept?' That’s exactly my text message to her," he said.

But Robredo has not yet replied to him, Panelo said.

He said Duterte could create a task force or a commission that Robredo would be heading if she accepts the offer.

Robredo reportedly did not receive any text message from Panelo.

She also said that if the Palace has no respect for her, at least it should have respect on her position.

If Duterte was serious with the offer, she has said it should be done formally and not just through a text message. Celerina Monte/DMS