TEHRAN, Iran (AP) _ Iranian Parliament Speaker Hashemi Rafsanjani today showed reporters the Bible he said was sent to Iran by President Reagan and said the U.S. leader was courageous but undercut by political rivals.

Rafsanjani displayed the leather-bound ''Open Book Bible-Expanded Edition'' at a news conference, holding it open to the title page, which was signed Ronald Reagan and had a handwritten New Testament verse:

''And the Scripture, foreseeing that God would justify the Gentile by faith, preached the gospel beforehand to Abraham, saying, 'All the nations shall be blessed in you.' Galatians 3:8, (signed) Ronald Reagan, Oct. 3, 1986.''

In Washington, White House spokesman Larry Speakes said he did not know whether Reagan signed the Bible. When asked whether he would ask the president, he said he would not and refused to say why.

In the rare meeting with foreign reporters, the Iranian offical praised Reagan for seeking better relations with Iran and for saying there was no evidence Iran was responsible for any terrorist acts in the past year and a half.

''I think this is a courageous statement by Mr. Reagan, contrary to the propaganda in the United States against the Islamic Republic of Iran,'' Rafsanjani said.

But he said Reagan was old, weak and in bad health and unable to counter unspecified rivals within his Republican Party.

''He acted weakly and has been defeated,'' Rafsanajani said.

Rafsanjani, considered the second most powerful man in Iran after revolutionary leader Ayatollah Ruhollah Khomeini, said the United States' most recent attempt to renew contacts through Iran's arms dealers was made a month ago in Frankfurt, West Germany, but that Iran rejected the initiative. A Mr. Dunbar of the U.S. State Department was in the delegation, he said.

''I think the time is not right that we have talk or discussion with the United States,'' Rafsanjani said through an iterpreter.

Sources in Washington last week said Secretary of State George P. Shultz told a House committee that he sent a State Department team and CIA negotiators to Europe on Dec. 6 to meet with Iranian representatives, but that the State Department officials refused further arms-for-hostages deals and the channel of communications was shut down.

Former U.S. national security adviser Robert McFarlane, who visited Tehran in last May with a planeload of arms as part of the Reagan administration 's overture to Iran, has denied reports he carried a Bible with him. But he said Jan. 20 on ABC's ''Nightline'' that a Bible was delivered by a U.S. delegation that met Iranians subsequently in West Germany.

Rafsanjani said the Bible was not brought by McFarlane, but by another U.S emissary whom he did not identify.

Rafsanjani displayed a photocopy of a false Irish passport he said were carried by McFarlane on his visit to Tehran in May.

One passport had McFarlane's picture, but gave his name as Sean Devlin. It said he was born in Dublin on Aug. 14, 1937, lived in Ireland, had hazel eyes and was 5 feet, 10 inches tall.

The journalists who met with Rafsanjani, mostly from the foreign press, underwent a rigorous security check at the gate of the Parliament complex in central Tehran. They were required to leave behind watches, wallets, rings, book and all other personal items except money, a pen and a note pad.

Only cameras and tape recorders that had been left overnight for inspection were allowed in the hall for the news conference.

Rafsanjani said he had no information on the situation of Anglican Church envoy Terry Waite, who has been in Beirut working to win freedom for Western hostages but has not been heard from in more than a week.

Rafsanjani said Waite was trying to help other people, and may himself now need help. ''If we can do anything for him we shall do so,'' he said.