The Philippine foreign minister on Wednesday slammed a former US ambassador as a "dismal failure" in an angry reaction to a secret cable published by anti-secrecy website Wikileaks.

Albert del Rosario assailed Kristie Kenney, who stepped down as US ambassador to Manila last year, after she allegedly criticised the Philippines' revered democracy heroine, the late president Corazon Aquino.

"She (Kenney) was a dismal failure in helping the Filipinos defend our democracy. It would seem that she preferred to be favourably looked upon by the (Philippine presidential) palace," del Rosario said.

Del Rosario's comments, via text message to AFP while he was in Beijing, were in response to requests for a reaction about a leaked cable apparently sent by Kenney in July, 2009.

According to the Wikileaks documents, Kenney wrote that Aquino had been a weak, tarnished leader who did not do enough to fight corruption.

Aquino led the "People Power" revolution of 1986 that overthrew dictator Ferdinand Marcos, then served for six years as president.

Her son, Benigno Aquino, was elected president in July last year in a landslide victory, partly due to the outpouring of public sympathy for his mother after she died of cancer in August, 2009.

The comments from Del Rosario, a key member of the latest Aquino administration, about Kenney referred to what he indicated was her apparent desire to curry favour with the president of the time, Gloria Arroyo.

Aquino's administration has repeatedly accused Arroyo of vote fraud and massive corruption during her nearly 10 years in power.

Kenney, now the US ambassador to Thailand, replied to a discussion on the microblogging site Twitter about the cable with a short message saying: "Good morning! Don't believe all you read."

The US embassy said in a statement it would not comment on the Wikileaks cable.