They said the order would direct the new administration to look at each Guantanamo case to see if the detainee can be released or if he should still be held, and if so, where.
Many of the detainees at the prison in Cuba are cleared for release, and others could be sent back to their native countries to beheld there.
But many nations have resisted Bush administration efforts to repatriate the prisoners.
The Obama advisers said it was hoped that nations that had initially resisted taking back the detainees would be more willing to do so after dealing with the new administration.
What remains the thorniest issue, the advisers said, is what to do with the rest of the prisoners, including at least 15 so-called "high value detainees".
If the detainees were transferred to US soil they would have legal rights they were not entitled to while imprisoned in Cuba.
It is also not clear if they would face trial through the current military tribunal system or in federal civilian courts and concerns have been raised about where they would be imprisoned.
More hunger strikes
The news of Obama's reported imminent order to shut Guantanamo comes as the US military said the number of inmates on hunger strike there had risen by eight to 42.
But Gitanjali Gutierrez, a lawyer for human rights group Centre for Constitutional Rights said that based on interviews with prisoners and letters the men
have sent to lawyers, more than 70 inmates were not eating in protest against their continued confinement.
More Guantanamo prisoners are on hunger strike than at any time since the spring of 2006.
Navy Commander Pauline Storum, a spokesperson for the prison, said no detainee was in danger but 31 inmates were being force-fed, which happens after a detainee either had gone three weeks without a meal, had fallen below 85 per cent of his ideal body weight, or if a doctor has recommended it as a medical necessity to preserve a his life.
Officials gave varying possible reasons for the spike in the number of inmates refusing to eat, including Obama's forthcoming inauguration and the anniversary of the arrival of inmates at the facility.
Detainees were first brought to Guantanamo on January 11, 2002.