President Barack Obama’s Hawaii vacation is being delayed by unfinished business in Washington, but First Lady Michelle Obama and daughters Malia and Sasha are going ahead with their trip this weekend.

A statement from Michelle Obama’s office Friday said the rest of the family — including the first dog, Bo — will depart for Honolulu on Saturday as originally scheduled for the holidays.

The president won’t fly to Hawaii until Congress’ session is complete.

"If I had to guess, I would say Wednesday," press secretary Robert Gibbs told reporters Friday morning when asked about the timing of Obama’s departure.

The family won’t take Air Force One, instead flying on a C40B, a version of the Boeing 737 that the first lady’s office described as one of the White House fleet’s smaller and most efficient planes.

The entire Obama family will return to Washington on Jan. 1.

Bo, the Obama’s 14-month Portugese water dog, will be here under the state Department of Agriculture’s 5-Day-or-Less program,which allows dog and cat owners to bring their pets for short visits.

Janelle Saneishi, the state Agriculture Department spokeswoman, said the Obamas had to meet the criteria for the progam and started preparing for Bo’s visit earlier this year.

Bo has to have been vaccinated at least two times, implanted with an electronic microchip and have completed a blood test to ensure that the pet is free of rabies.

"Hawaii is the only rabies free state," Saneishi said, "and that is the only reason for these restrictions."

An Air Force veterinarian will check Bo upon arrival at Hickam to examine Bo for ticks and to make sure all the paperwork is in order, Saneishi said.

State law requires dogs and cats not meeting all of the specific 5-Day-or-Less program requirements to be quarantined for up to 120 days upon arrival.

President Obama has pledged to remain at the White House for as long as Congress remains in session. It’s the second year he’s had to delay his annual visit to his home state for the holiday season. In 2009, he did not leave until Christmas Eve as lawmakers voted on his health care reform plan.

Gibbs said the president will continue to work the phones until he leaves, urging lawmakers to act on the New START treaty, a repeal of the "don’t ask, don’t tell" policy banning gays from serving openly in the military, and the DREAM Act, a bill to legalize some undocumented immigrants who were raised in the United States.

The Senate will take up both the "don’t ask, don’t tell" repeal and the DREAM Act this weekend. Earlier efforts to pass both fell short. The Senate then would likely hold a final vote on the New START treaty Tuesday or Wednesday.

A spokesman for the first lady said she would have no public appearances after she and her daughters arrive. The president will also likely maintain a low profile once he joins them, though his trips to the golf course, beaches or for shave ice will include the traveling press pool here to document his activities.

Obama has traveled to the islands for years to visit family and friends, but only once as president. He came twice as a candidate in 2008 — first for a break before the Democratic National Convention, and later to visit his ailing grandmother, who helped raise him here. He returned as president-elect that winter.

Since taking office, Obama has made nine vacation trips totaling all or part of 49 days, according to CBS Radio’s Mark Knoller, the unofficial statistician of the White House press corps. That includes summer trips to Martha’s Vineyard and last year’s Hawaii trip.

By comparison, George W. Bush had spent all or part of 130 days on vacation through the same point in his presidency, most at his ranch in Crawford, Texas.

Obama has also made 15 trips to the presidential retreat at Camp David, compared with 48 by Bush.

The Associated Press, Tribune Washington Bureau and Star-Advertiser Reporter Gregg K. Kakesako contributed to this story.