Some 5,000 die-hard fans of the former movie star were transported by buses from the provinces while others marched on foot, bearing pictures and slogans of support.
Anti-riot police armed with batons and shields blocked strategic areas such as North Avenue in Quezon City leading to the Veterans Memorial Medical Center (VMMC) where Estrada has been detained for nearly one year now following his arrest on corruption cases, including the capital offense of plunder.
The protesters kept their distance to avoid a confrontation with the riot police who were under strict orders to quell any disturbance.
There was a brief standoff as Estrada fans slowly approached a key intersection leading to the hospital, bringing traffic to a standstill.
Police later allowed them to set up a platform to conduct a program.
The protesters waved signs saying "Happy Birthday President Joseph Estrada! We love you!" as firetrucks and armored vehicles stood by on the hospital grounds, ready to disperse the crowd.
The crowd sang "Happy Birthday" to the jailed former president who sytayed in his suite.
Estrada’s wife, Sen. Luisa Ejercito, said she was told by rally organizers that police had forcibly stopped several buses carrying Estrada supporters.
She accused President Arroyo of "pure harassment" to prevent the pro-Estrada marchers from airing their views.
"I want to call on the police that they should stop doing those things," she told a local radio station.
Authorities have been on the alert to prevent any repeat of the bloody riot staged by Estrada supporters at Malacañang gates on May 1 last year.
In an open letter published by a newspaper yesterday, Estrada called on the police to show restraint towards his followers.
"I know you are following the orders of someone above you, but I hope you will remember that those you hurt are your fellow Filipinos," the letter stated.
Estrada was accused of amassing some P4 billion during his 30-month rule which ended on Jan. 20 last year. He has repeatedly denied all allegations against him, and insisted he was still the legal president.
Mrs. Arroyo said apart from "peace of mind," she also wished her predecessor "as comfortable conditions as possible" while in detention at the VMMC.
"I’ve always abided within the parameters (of the law), of letting justice take its course and (to) make life as comfortable for him as possible," the President said.
She added that Estrada should consider himself fortunate as he is housed in an air-conditioned suite and not in jail.
Ejercito marked her husband’s birthday by making a round of blighted areas in Cavite, accompanied by Gov. Irineo "Ayong" Malicsi, a known ally of the former president.
Meanwhile, Senior Superintendent Leonardo Espina, spokesman for the Philippine National Police (PNP), said they had no intention of barring journalists from covering Estrada’s birthday celebration and the protest rally by his supporters.
Several local and foreign reporters complained that security personnel assigned at the VMMC barred them on Thursday evening from the hospital compound.
Under the guidelines set by the anti-graft court Sandiganbayan for media interviews with Estrada, the PNP should be notified prior to the interview.
"Not a single PNP unit received a copy of the Sandiganbayan order. This is pure and simple... we have not received (any) orders from the court," Espina said.
In another development, opposition Sen. Teresa Aquino-Oreta decried the "systematic attempt" by the Arroyo administration to prevent Estrada supporters from massing into a large crowd, saying the move was tantamount to suppressing freedoms of assembly and expression.
Oreta noted that although Mrs. Arroyo had wished Estrada "peace of mind" for his birthday, her government "appears bent on thwarting the fulfillment of this wish by harassing not only the former President but his supporters as well."
In a statement, Oreta also denounced reports that anti-riot police had removed orange-colored ribbons tied by Estrada loyalists along the road leading to the VMMC.
"What compelling reason did the police have to remove these ribbons when this act of expression neither causes any disturbance nor incites anyone to do anything unpeaceful?" Oreta asked.
"It now looks like the government’s policy of maximum tolerance has been replaced by a policy of maximum suppression," she added.
Meanwhile, two groups of urban poor urged the Estrada supporters to "go beyond the Erap issue" during their planned May 1 protest actions.
Describing their group as the "third force," members of the Kongreso ng Pagkakaisa ng Maralitang Lungsod (KPML) and the Zone One Tondo Organization (ZOTO) said they should fight for their rights instead of demanding Estrada’s return to power.
"On May 1, let us commemorate not the struggle to restore the Estrada presidency, but to reclaim our rights to live decently as human beings. We should struggle (for) the rights and welfare of the toiling majority," said KMPL leader Jess Panis.
KMPL and ZOTO members marched to Mendiola near Malacañang yesterday to demand for the implementation of pro-poor reforms by the Arroyo administration. — With reports from Marichu Villanueva, Christina Mendez, Mayen Jaymalin