Asked on Monday if he thought it a safe assumption it really was al-Qaida leader's voice on the tape, Straw replied: "Yes."
Meanwhile, an unnamed CIA official told Reuters "after conducting a technical analysis, the CIA's assessment is that it is likely bin Ladin's voice".
The tape is probably going to embarrass Western leaders who have so far failed to capture bin Ladin, whom they accuse of masterminding the 11 September 2001 attacks on the United States.
In the recorded message, broadcast exclusively by Aljazeera on Sunday, bin Ladin condems Middle Eastern governments for betraying Arab and Muslim causes and urges his coreligionists to resist the West.
The al-Qaida leader urged Muslims to continue jihad against what he described as "conspirators against Muslim nations".
He also attacked Arab governments for failing to resist US military and diplomatic moves in the Middle East as well as making compromises in their support of the Palestinian national cause.
Bin Ladin made reference to the 14 December capture of ousted Iraqi leader Saddam Hussein, suggesting the recording was made quite recently.
He referred in particular to the occupation of Iraq, the US-backed "road map" for settling the Israeli-Palestinian conflict, as well as the alternative Geneva peace plan between the Palestinians and the Israelis.
Arab rulers scorned
Bin Ladin slammed rulers of Arabian Gulf countries and scorned their ability to repulse any possible US attack on their countries.
Al-Qaida leader called for Arab and
Muslim leaders to be overthrown
He also criticised what he describes as the persecution by certain "outlaw" regimes of their citizens.
The al-Qaida leader went on to condemn Muslim rulers' inability to stand up to the US, criticising their compromises with reference to the Palestinian cause.
He attacked what he called their "stand against Palestinian resistance as took place at the Sharm al-Shaikh summit in 1996 (an anti-terrorism summit), and at the Beirut Arab summit (2002)".
Bin Ladin condemned certain countries for "stopping financial aid to the families of Palestinian martyrs", meaning human bombers. He rejected the US-backed road map peace plan, which stipulates an end to armed resistance against Israeli occupation.
The al-Qaida chief also excoriated the six Arab states of the Gulf Cooperation Council for welcoming members of Iraq's US-installed transitional Governing Council.
Dismissing the economic achievements of the Arab world, bin Ladin said Spain's economy alone was much larger than that of all the Arab countries put together.
He blamed the decline of Arabs and Muslims on their abandonment of Islam as a system of government and state, and called on Muslims to establish a council of wise men to rule after the overthrow of all regimes in the Arab and Muslim world.
The former mujahidin commander in Afghanistan said such a council would unify Muslims and Arab positions and raise the banner of jihad to stop what he calls the West's attacks against Muslims.
Bin Ladin also criticises moves to change educational curricula in Muslim countries and warned of a religious and economic war by the West, aimed at dominating other Gulf countries after the occupation of Iraq.