Despite Congressional leaders’ failure to establish a bicameral committee to probe the emergency response to Hurricane Katrina, House and Senate panels tasked with the investigation are moving ahead with a coordinated effort.

Senate Homeland Security and Governmental Affairs Chairwoman Susan Collins (R-Maine) said Tuesday she and ranking member Joe Lieberman (D-Conn.) expect to meet with Rep. Tom Davis (R-Va.), who is leading his chamber’s investigation, later this week to discuss their plans.

“We are going to coordinate our efforts,” said Collins, who spoke at the Christian Science Monitor’s “Sperling Breakfast” with print journalists.

The Maine lawmaker noted that staffers from both panels have already begun working together, citing the participation of Senate aides in a House-led interview of former Federal Emergency Management Agency Director Michael Brown on Monday, in preparation for his Tuesday appearance before Davis’ House Select Bipartisan Committee to Investigate the Preparation for and Response to Hurricane Katrina.

“It’s possible at some point we may do some joint hearings or collaborate on a report, or we may divide up some of the issues,” Collins added.

Responding to the chairwoman’s remarks, a Davis spokesman said: “Chairman Davis has said all along that he’s very happy and willing to work with the Senate.”

In the meantime, Collins said the committees will submit a “joint document request” to several federal agencies today. According to a Senate aide, the list of agencies included in the request had yet to be finalized Tuesday.

Collins stated that she also expects to request documentation from the White House during the course of the investigation.

Although House and Senate leaders had initially sought to create a joint committee to conduct the investigation, Democrats in the Senate blocked those efforts, citing concerns about the majority’s ability to direct the scope of the investigation as well as call witnesses regardless of Democratic input.

While the House succeeded in creating its own select panel, Minority Leader Nancy Pelosi (D-Calif.) has refused to appoint members of the Democratic Caucus to the committee.

Instead, House Democrats have persisted in calling for an independent commission, accusing Republicans of being unable to adequately conduct oversight of the disaster.

Pelosi continues to call the panel a “sham,” even though she gave her blessing to three Democrats from the Gulf Coast — Reps. William Jefferson (La.), Gene Taylor (Miss.) and Charlie Melancon (La.) — to participate.

One Democratic leadership aide said those three Democrats are asking “pointed questions” and playing an important role in the probe, even though the party itself believes the panel isn’t the appropriate forum for investigation.

“You have 11 guys who don’t really know much about it, and we have three [Democrats] asking questions who have been directly involved in the recovery effort,” the staffer said. “They are making the case. The one asking the toughest questions is Gene Taylor.”

The hearings went on Tuesday as Democrats continue to disagree over whether Pelosi is correct to protest formal party participation.

House Minority Whip Steny Hoyer (D-Md.) acknowledged that there are differences of opinion within the Caucus about whether to continue the boycott, saying Tuesday that there are “discussions” ongoing “at all levels” about whether it is the right approach.

But even with those varying opinions, Hoyer insisted that no Democrat disagrees with the formation of an independent commission.

When asked how long Democrats are willing to sit on the sidelines while the select committee moves ahead, Hoyer said: “Let’s see how long the American public is prepared to wait” for an independent commission.

Rep. Alcee Hastings (D-Fla.), who has introduced legislation that would create a 9/11-style independent commission, announced a discharge petition Tuesday that could force a floor vote on the proposal as early as November. Hoyer also said that Democrats will “be watching” the Republicans to see whether they actually get answers to concerns about the Katrina response or “simply create a scapegoat” out of Brown.

He was quick to add, however, that Democrats aren’t waiting to see how the committee hearings proceed to make a decision whether to appoint Members to the panel at a later date.

“There’s no such ‘depends’ at this point in time,” Hoyer said.

Collins called the House Democrats’ decision not to take seats on the panel “unfortunate,” but asserted that their absence would not impact the investigation.

“This shouldn’t be a partisan investigation. I’m committed to making sure that the Senate investigation is fair, bipartisan and constructive,” Collins said. “Tom Davis, from my experience in dealing with him, will ask the tough questions, do a no-holds-barred investigation, but I think that the Democrats on the House side are trying to lessen the credibility of the investigation by refusing to participate.”

Erin P. Billings contributed to this report.