US lawmakers will have their first chance to formally question Chuck Hagel, President Barack Obama's defense secretary nominee, on January 31 when the Senate convenes a confirmation hearing.

The Senate Armed Services Committee announced Wednesday it will hold an open hearing, with the possibility of a follow-up session that would be closed to the public and the press.

The hearing will be closely watched in Washington and abroad to see whether the most controversial appointment of Obama's new cabinet can win sufficient support from senators who have expressed deep concerns about Hagel's stances on Iran and Israel.

Hagel is a Republican former senator and decorated Vietnam War veteran who backers like former secretary of state Colin Powell say is "superbly qualified" to take over from Leon Panetta at the head the Pentagon.

But some Republicans have openly expressed doubts or outright hostility to the nomination, including Senator James Inhofe, who targeted Hagel's soft position on Tehran's nuclear drive and his apparently less-than-convincing support for Israel.

"Unfortunately, as I told him during our meeting today, we are simply too philosophically opposed on the issues for me to support his nomination," Inhofe said Tuesday.

Hagel has been lambasted by Republicans for his 2001 vote against imposing tougher sanctions on Iran. And his opposition to the Iraq war surge is also a factor in former colleagues expressing opposition to his confirmation.

Democratic Senator Chuck Schumer, a hawkish supporter of Israel over the threat posed by Iran, said he met with Hagel on Monday and had been convinced to endorse him.

"Based on several key assurances provided by Senator Hagel, I am currently prepared to vote for his confirmation," Schumer said, adding that Hagel had cleared up questions related to past positions and statements, and vowed to do "whatever it takes" to stop Iran getting nuclear weapons.

Hagel in the past has favored opening direct talks with Hamas, and refused to sign a letter calling on the European Union to designate Hezbollah as a terrorist group.

He has also drawn sharp anger from pro-Israel lawmakers with his comments about what he described as the "Jewish lobby" in Washington.

Hagel, in his defense, has said he did not vote for some resolutions backed by pro-Israel organizations because he viewed them as counter-productive.

The Democratic caucus holds 55 of the Senate's 100 seats. Should all Democrats vote for confirmation, they will need five Republicans to get on board in order to overcome any legislative blocking tactics.