Opposition presidential candidate Corazon Aquino, in a message intended for Washington, warned the Philippines' friends abroad today not to "support a failing dictator," as the government media portrayed statements Monday by President Reagan as virtually endorsing the reelection of President Ferdinand Marcos.

"In this time of need we will learn who our real friends are," Aquino said, as vote counting continued into a fifth day after Friday's controversial election. "Understand that we have won and we will take power."

Aquino campaign workers said her remarks came in response to the government media's portrayal of statements by Reagan and other U.S. officials as continuing support for him despite widespread charges of electoral fraud.

Reagan on Monday played down reports of fraud and said results in the election so far prove that "there really is a two-party system, obviously good" in the Philippines.

Commenting on the fraud issue today, Cardinal Jaime Sin, the Roman Catholic archbishop of Manila, publicly called Marcos "a liar" for having accused a citizens' poll-watching group, as well as priests and nuns, of cheating in the election.

While publicly insisting that Aquino has won Friday's election, the opposition has begun acknowledging that Marcos is likely to be proclaimed the winner by the Batasang Pambansa, or National Assembly, which his ruling party controls with a two-third majority.

The process of canvassing votes and declaring a winner inched forward there this evening, with the first official opening on the legislative floor of metal boxes that contain tally sheets for election returns. Opposition members who charge the figures may be fraudulent attempted delaying actions throughout the eight-hour session, which closed without starting the actual counting.

Marcos said today that he intends to "abide by the results of the parliamentary canvass and proclamation" and appealed to the opposition to do the same. In a press conference, he announced his intention to form a Council of State and invite opposition members, including Aquino, to join it. He said the council would function as "the highest advisory body of the country" and submit "suggestions" to his government.

"Let's forget about all this childish display of petulance just because our figures don't agree," Marcos said. "I think this can be settled, not by fisticuffs or shooting or any violence, but by a quiet, simple procedure of comparing the official election returns now."

Tension has risen further between Marcos and the opposition in the past two days because of the shooting deaths of two Aquino supporters, including the former governor of the central province of Antique.

Evelio Javier, chairman of Aquino's campaign in the province, was shot to death this morning by six masked men in the plaza of the capital town of San Jose, Aquino's press office reported.

The press office quoted Antique Gov. Enrique Zaldivar as reporting that the killers were led by a Philippine Constabulary captain and an ex-convict and that they used two vehicles belonging to Arturo Pacificador, a member of the assembly from Marcos' ruling party.

Pacificador defeated Javier in a May 1984 election in which several supporters of the opposition candidate were killed in an ambush by gunmen linked to Pacificador by a subsequent investigation.

Pacificador, now assistant majority floor leader, is a member of a newly formed presidential election tribunal that will settle any disputes over the assembly's proclamation of a new president. Manila authorities have blamed the killing on Communist rebels.

On Monday, a campaign worker for Aquino was shot to death by a sniper following a prayer rally at which Aquino spoke.

Aside from peaceful protest demonstrations and vigils outside vote-counting centers, Manila so far has maintained a business-as-usual atmosphere. Opposition politicians cautioned that this could change if Marcos was officially proclaimed president for another six-year term or if Aquino called on her followers to take to the streets.

In her statement today addressed to "friends abroad," Aquino called Friday's poll "one of the most shameful electoral frauds ever perpetrated against a people in the name of democracy."

Appealing to "all friends of democracy," Aquino said, "Do not make the mistake, in the name of short-sighted self-interest, of coming to the support of a failing dictator."

Aquino, looking somber, refused to answer questions after reading her statement.

In a separate news bulletin, she appealed to "our brothers in the military and the police" to come to "the gallant defense of our peace." She suggested that they emulate a group of employes of the Marcos-appointed Commission on Elections who walked out of a vote-counting center to protest alleged falsification of the tally.

Reagan's statements on Monday buoyed spirits in the Marcos camp, where the United States has often been viewed as siding with the opposition.

Asked how he felt about the statements, Information Minister Gregorio Cendana replied: "Pretty good."

Officials also praised Sen. Paul Laxalt (R-Nev.), whose remarks earlier this week that U.S. election observers saw too little to make an overall judgment received prominent play in the progovernment press here.

During the assembly session today, the legislature voted 117-43 to kill an opposition motion to put off consideration until canvass documents from all 147 voting districts in the country have arrived. So far, the assembly has documents from only 96. Opposition members argued unsuccessfully that the constitution prohibits consideration of partial returns.

Under Philippine law, the National Assembly is charged with adding up the returns and declaring a winner. Members of Marcos' ruling party, which controls two-thirds of the 192 seats, are talking of proclaiming a winner on Friday or earlier.

Before any vote counts could be taken today, the assembly adjourned for lack of a quorum and will resume the process at 3 p.m. Wednesday.

Two other unofficial counting operations continued to move ahead and contradict one another today. The latest count of the citizens poll-watching group known as Namfrel showed Aquino in the lead 6.93 million to 6.28 million.

The government's Commission on Elections had it the other way around, with Aquino losing 5.60 million to 6.15 million.

Namfrel, meanwhile, was reported to be considering suspending its count.

Marcos has gained against Aquino in the last day and Namfrel officals are understood to be worried that her lead will erode further as blocs of votes for Marcos come in from areas where Namfrel had no observers on election day.

Namfrel feels that many of those votes were fraudulently obtained. By putting them on its boards, however, the group could be seen as sanctioning them.