Blair will talk via video-link on Tuesday to the bipartisan committee headed by former US secretary of state James Baker, which is seen as the means through which Washington could change course on Iraq.
A spokeswoman said the prime minister -- who has been in touch with the Iraq Study Group since its inception -- would ensure that Baker and his colleagues were "fully briefed on UK ideas".
But she refused to be drawn on reports in The Guardian newspaper on Saturday that he would push the US administration to begin talks with Syria and Iran as a way of breaking the deadlock in Iraq and the Middle East.
The newspaper, citing unnamed British officials, said Blair would not call for the withdrawal of coalition troops, but was persuaded that Bush is open to a change of strategy in Iraq, which is gripped by spiralling violence.
The same sources forecast that the Baker panel would call for an acceleration of the "Iraqization" of the police and army as well as advocate greater political co-operation within Iraq.
Blair would also reportedly stress the link between progress in Iraq and re-energising the Middle East peace process.
The prime minister said on November 1 that he intended to visit the region by the year end.
The Guardian said British officials believe that the White House is "open to the principle" of dialogue with Syria, while new Defence Secretary Robert Gates -- a member of the panel -- is persuaded of re-opening contacts with Iran.
Earlier this month, Blair sent his most senior foreign policy advisor, Sir Nigel Sheinwald, to Damascus, to meet Syrian President Bashar al-Assad and other senior figures.
Blair's official spokesman said London hoped Syria would play a "constructive role" in the push for peace in the wider region and cease its support for radical groups such as Lebanon's Hizbullah.
Neither Syria nor Iran wanted to see the break-up of Iraq nor the spread of sectarian violence, he added.
Blair's decision to talk to the committee was immediately condemned by the leader of Britain's opposition Liberal Democrats, which opposed the war.
Its leader, Menzies Campbell, said it was "intolerable" that Blair was prepared to give evidence to the US committee when he is resisting a parliamentary inquiry into the war here.

Copyright AFP (Agence France-Presse), 2006