Kofi Annan said on Monday that if the Iraq "situation improves, we will be ready to go back... But we don't need to be in Iraq 100% to do what we can do or offer assistance".
He added: "So we are looking at what we can do outside and cross-border and eventually what we can do inside."
Annan also promised on Monday that he would name a chief envoy for Iraq shortly, following the August kiling of his special representative, Sergio Vieira de Mello.
Under pressure from the United States, Iraqis and others to send international staff back into Baghdad, UN officials said Annan was looking for a representative of stature.
Iraq interim government
The chief envoy might not play an important role initially, but could have major responsibilities after an Iraqi interim government takes over in June, they said.
"(If the Iraq) situation improves, we will be ready to go back... But we don't need to be in Iraq 100% to do what we can do or offer assistance"
UN Secretary General
Annan withdrew foreign political staff from Baghdad after the 19 August bombing of a Baghdad UN compound that killed 22 people, including Vieira de Mello.
Since the United States and the Iraqi Governing Council announced last week they wanted an interim Iraqi Government by June, Annan had come under pressure to play a political role.
Calls for the United Nations to return to Iraq had come in the last few days from the US, Italy, Germany and France.
"I think it's time now with this new plan for the United Nations to determine whether or not circumstances will permit it to play a more active role inside the country," US Secretary of State Colin Powell said on Monday.
"We want the UN to play a role and it is part of our plan in moving forward," he added.
Annan said he also spoke to Jalal Talabani, the Kurdish leader who is this month's president of Iraq's interim Governing Council.
Talabani told him the Governing Council would "need UN assistance and advice in implementing the new decisions which have been taken".
On Monday, the deputy US national security adviser, Stephen Hadley, briefed Annan on the new American timetable for ending the occupation.
Vieira de Mello (L) was killed in
the UN's Baghdad headquarters
But Annan repeated that an October Security Council resolution called on the United Nations to play a role in Iraq "as circumstances permit", a reference to safety conditions.
Transfer of power
He is under pressure from senior UN officials not to expose staff to harm.
The Bush administration's decision to speed the transfer of power won praise from Annan last week. He had long agreed with France, Germany and others in advocating quicker restoration of Iraqi sovereignty.
Annan has never championed a UN administration or military role for Iraq, as in Kosovo or East Timor. But he has argued that the United Nations play a role independent from the coalition ushering in democracy in Iraq.
The Iraqi Governing Council is required to submit its new plans to the UN Security Council by 15 December.