WASHINGTON.-Both sides in the Pakistani civil strife are telling Washington its pending decision of whether or not to give economic aid to the Pakistani Government is all important .

Top West Pakistani economic advisers met earlier this month with President Nixon, his security adviser Henry A. Kissinger, Secretary of State William P. Rogers, and others to persuade them to help out on grounds that the Pakistani Government stands on the verge of bankruptcy. The United States had been contributing some $200 million a year to Pakistan through the 11-nation aid-to- Pakistan consortium aid suspended when civil war broke out March 25.

The U.S. now is reported ready to participate in a standby loan of roughly $100 million to be given by the consortium this summer. The offer is supposedly contingent on some kind of acceptable political settlement between the sides and development of a realistic economic program for spending it.

BANGLA DESH OPPOSES AID

Meanwhile, representatives of the secessionist Bangla Desh government, claiming to speak for 75 million Bengalis in East Pakistan or more than half Pakistan's total population, are working, largely through public opinion channels in this country to persuade the U.S. Government to have no part in any aid effort. They reason it would only prolong the war.

Speaking to this point of view in a recent press conference, Rehman Sobhan, former economic adviser to Sheikh Mujibur Rahman, leader of the Awami League, said that despite government promises that much of the money would go for relief efforts in East distribution machinery.

The net effect, he said, would be military rather than humanitarian aid.

Mr. Sobhan, an economics professor at the University of Dacca ( now shut down under martial law ), termed Army efforts to quash the Bengali independence move "genocide." He said the brutality of the methods used had done much to solidify Bengali commitment to its quest for nationhood.

UNION REJECTED

"There is absolutely no question of our union with them (the Pakistan Government)," he insisted. "We are fighting for the right of determination, and it is essentially a question of time now-what price has to be paid."

Asked to comment on current efforts of the Pakistan Government to achieve some kind of political settlement, he said that the government has been forced to "dig very deep into the political gutter" to find Bengalis willing to cooperate in any arrangement and that those chosen have almost no support from Bangla Desh supporters. "How long the war goes on will depend on whether the world's aid donors choose to underwrite it," he emphasized.

Although the U.S. State Department is on record as deploring the heavy loss of life in East Pakistan and as hopeful that a peaceful political accommodation can be reached, it is pointing no fingers. The civil war is officially viewed as an "internal" matter.

EMBASSY TENSION NOTED

The depth of feeling involved in that "internal" fight is mirrored in the tension noted by Washingtonians in the Pakistani Embassy here . So far this spring, two Bengali civil servants have been fired for their purported participation in rebel activities.

Gousuddin Ahmad, an assistant in the accounts division since 1965, was dismissed in April when he admitted he participated in March 29 demonstrations in front of the Capitol and White House.

A. R. Khan, an assistant education officer with the embassy since February, 1964, was fired earlier this month for having attended a congressional subcommittee hearing May 11 on the East Pakistan situation.

Mr. Khan says he had permission to take a leave of absence that day, that an embassy counselor and other West Pakistani staff members were present at the public hearing and received no criticism, and that he took no active role in the hearing.

INQUIRY STARTED

"His job is to look after education problems of Pakistani students in this country," retorts the press spokesman for the Pakistan Embassy. "He has no business attending Senate or House debates."

A hand-circulated communiqué from the embassy's second secretary has gone out to the staff asking if anyone has knowledge that two staff members, both Bengalis, participated in the March 29 antigovernment demonstrations in Washington.

The memo notes that both men have denied participation and that the ambassador decided to institute an inquiry. The information is requested by Monday, May 24, Akm Fazlu Bari, one of the two men, says: "I did not participate physically ill the demonstration. I may have passed by, but I was a spectator-I wasn't carrying a placard or making speeches."

OPEN LETTER CIRCULATED

Mr. Bari is one of three Bengali employees of the embassy to sign all open letter protesting the firing of Mr. Khan for alleged ''misconduct.'' They termed the action "humiliating and discriminating."

The writers say it makes "explicitly obvious the intention of the Government of Pakistan to extend its persecution of Bengalis even to those employed by that government here in the U.S."

The Pakistan Government interprets its actions differently:

"The point is that Pakistan's Government servants have, since the foundation of the country, been prohibited from participating in any political demonstration," says the embassy press spokesmen. ''Governments may change, people may change-but that is an iron rule which stays the same. Anyone who wants to participate in politics is offered a simple choice: resignation."

As to the charge raised by some that Bengalis have been given menial work in the embassies since the difficulty because they are not trusted, the press spokesman points out that the embassy minister (second in authority only to the ambassador), a Counselor, all economic secretary, and an economic adviser are all responsible positions and are held by Bengalis from East Pakistan .

While there have been no reports of similar tension in other Pakistani embassies around the world, the Washington case is regarded by some as one of the more blatant examples of what must be a fairly typical situation.