MANILA, Philippines -- Former presidents Corazon Aquino and Joseph Estrada rallied the public against efforts by President Gloria Macapagal-Arroyos allies in Congress to amend the Constitution.

While the two former leaders were not at the anti-Charter change rally in Makati City on Wednesday, their messages were read to the hundreds that converged on the intersection of Ayala Avenue and Paseo de Roxas.

"Huwag natin hayaan ang isang walang hiyang pang-aabuso sa ating pinakapayak na batas [Let us not allow this abuse to our fundamental law]," Aquino said in her message, which was read by her grandson Kiko Aquino-Dy.

"Kahit mahina ang aking katawan, matatag ang aking paninindigan laban sa katiwalaan [I may be weak, but my resolve to fight corruption remains strong]," said the former president, who underwent surgery for colon cancer last April.

Aquino said she felt "pain and sadness" because of the government betrayed the public's trust.

"It's painful to see all our gains being eroded," said Aquino, who led a bloddless uprising in 1986 that toppled the Marcos dictatorship and restored democracy in the country.

Estrada said that if the constituent assembly push succeeds, it will be the third time for Arroyo to violate the Constitution.

"Binalewala niya ang Constitution nang manungkulan siya noong 2001 at nuong Hello Garci scandal noong 2004 [She disregarded the Constitution when she assumed power in 2001 and during the Hello Garci scandal in 2004]," said Estrada in a statement read by his son San Juan City Major JV Ejercito.

Estrada was referring to the popular revolt in 2001 that ousted him from power and installed his then vice president, Arroyo, into power; and the leak of wiretapped recordings that showed alleged cheating operations that led to Arroyo's victory in the presidential elections in 2004.

Both former presidents urged the public to stay on guard against moves to change the Constitution.

"Nakalimutan na ng mga lumagda ng House Resolution 1109 ang pinakamataas na batas ng bansa. Hindi maaaring amendyahan ng mababang kongreso ang Constitution [Those who signed House Resolution 1109 forgot the highest law of the land. Congress cannot amend the Constitution," Estrada said.

Arroyo's allies in the House of Representatives approved HR1109 last week, calling on lawmakers to convene into a constituent assembly to amend the Constitution, even without the approval of the Senate.