Obama, holidaying in Hawaii, has made no public remarks on Israel's unrelenting military assault on the Palestinian territory, which has left more than 380 people there dead.
The former Illinois senator spoke out after last month's attacks in Mumbai and has made detailed statements on the US economic crisis.
But some fear that the US president-elect's reluctance to speak out on the Gaza raids could be sending its own message.
"Silence sounds like complicity," Mark Perry, the Washington Director of the Conflicts Forum group, told Al Jazeera.
"Obama has said that Israel has the right to defend itself from rocket attacks but my question to him is 'does he believe that Palestinians also have the right of self-defence?'"