A senior Iraqi official said today that Iran's "war of attrition" in the long- running Persian Gulf conflict has failed decisively but that there has been no sign from Tehran of willingness to move toward peace.

Deputy Prime Minister Tariq Aziz, who also serves as foreign minister, said Iraq has welcomed a Japanese proposal for mutual deescalation of the war. But so far, he said, the effort has not won support in Iran.

In a wide-ranging review of Iraqi military policy and diplomacy, Aziz said recent changes in attitude by the Reagan administration, which have been described by some as a "tilt toward Iraq," have brought Washington and Baghdad into much closer alignment and produced "a very agreeable atmosphere."

As a result, he said, he is actively discussing with the State Department an exchange of high-level official visits following the U.S. election to cement the improving relationship. Asked if this could lead to the restoration of U.S.-Iraqi diplomatic relations, which were severed in 1967, Aziz replied, "We will consider such a question in a positive way."

Aziz also made it clear that Iraq would like to move toward restoration of diplomatic relations with Egypt, which has been assisting Baghdad materially in the war against Iran.

He indicated that Iraq will seek agreement at the next Arab League summit meeting, which may be held as early as next month, to readmit Egypt, which was expelled in 1979 after signing a peace treaty with Israel.

If a common agreement on this point proves impossible, Aziz added, every Arab country will be free to consider its relations with Egypt "by itself, unilaterally."

Most of the interview dealt with the war in the Persian Gulf, which began with Iraq's attack against Iran four years ago last month and which continues to be considered one of the most dangerous conflicts in the world today, as well as one of the bloodiest in modern times.

Aziz said that an Iranian decision early last year to wear down Iraq with a "war of attrition" was thwarted by Iraq's attacks on Persian Gulf oil shipping, which damaged Iran economically, and by the simultaneous buildup of the Iraqi economy.

The current growth of confidence is such that foreign countries are again willing to undertake large-scale projects in Iraq on a deferred payment basis, with "hundreds of millions of dollars" in new contracts recently awarded, he said.

Iraqi oil exports are now up to about 1 million barrels per day, he said, a figure that according to U.S. sources represents an increase of nearly 50 percent in the past few months.

Aziz said the expansion of the present oil pipeline through Turkey will increase the figure to 1.5 million barrels per day near the end of 1985. The opening of a new pipeline through Saudi Arabia, due to become fully operative in 1986, will allow Iraq to export another 1.7 million barrels per day.

All this would bring Iraq's oil exports very close to prewar levels, he said, and would provide a basis for long-term stability and growth, even if Iran continues to deny Iraq the ability to export its oil through the Persian Gulf.

A third, much-discussed pipeline project, for which the United States has agreed to provide nearly $500 million in Export-Import Bank financing, has been put on the shelf for the time being because of uncertainty over whether Israel would permit the oil to flow, according to Aziz. This pipeline would cross Jordan and terminate at the Gulf of Aqaba close to Israel.

Resumed exports of Iraqi oil through the Persian Gulf are envisioned in the three-part Japanese formula for deescalating the war. Aziz said the proposal was discussed in August with Japanese diplomats and a few days ago in New York with Japanese Foreign Minister Shintaro Abe.

The other major points are agreement by Iraq that it will not use chemical weapons, which were reportedly used against Iranian troops some months ago, and agreement by both sides to freedom of navigation in the Persian Gulf, which would involve an end to attacks by both sides on oil tankers and other shipping.

"We discussed this with the Japanese in a positive and serious way," said Aziz.

While saying that such a plan could have its dangers if it served mainly to relieve the pressure against Iran temporarily, he declared that "we are not opposed to a step-by-step process" if it is implemented carefully.

Aziz said that, while Iraq did not give its endorsement, it did not object to the Japanese exploration. He said he had no word that Iran is interested. U.N. diplomats said Iranian Foreign Minister Ali Akbar Velayati has been very negative in private, as in public, about any accommodation with Iraq since arriving here a week ago.

Regarding the Iranian forces that have been arrayed along the Iraqi border in attack positions since early this year, Aziz said he believes that "sooner or later" they will launch their long-awaited ground offensive.

"We are prepared. We are ready to crush it," he said of the force now estimated by U.S. sources at 250,000 to 300,000 Iranian combatants. If and when the offensive fails, Aziz said, this will demonstrate "the bankruptcy" of Iranian policy for all to see.

Nevertheless, he declined to predict the Iranian reaction in such a case. Maybe Iran will realize it must change course to give up the war, but "maybe they will do the most crazy things," said Aziz.

Already, he charged, Iranian frustration in the Persian Gulf war is among the factors behind the attacks against U.S. Embassy buildings and the U.S. Marine headquarters in Beirut.

Iranian leaders, he said, decided on an "adventurous" course of terrorism against the United States and the West to prove to the Iranian people that they are capable of taking successful action despite setbacks in the Persian Gulf.