Turkey's parliament had blocked use of its territory for combat against neighboring Iraq, a decision that strained relations with the United States.
Use of the facilities during postwar reconstruction does not require parliament's approval.
In explaining the decision to allow coalition forces to use ports and airports, Foreign Minister Abdullah Gul cited a new U.N. Security Council (search) resolution that allows the United States and Britain to govern Iraq and use its oil wealth to rebuild the country.
Turkish politicians have said parliament would have been more likely to grant access to U.S. troops in the war if the operation had U.N. approval.
There was strong opposition in Turkey to the war, but Turkish companies are eager to participate in Iraq's reconstruction.
"Those countries that want to help Iraq and contribute to its reconstruction may benefit from Turkey's facilities," Gul said.
The foreign minister didn't say when the decision would go into effect and he didn't mention military bases. Other officials, however, said bases would be available for logistical support.
Turkey is already allowing coalition forces to bring supplies into northern Iraq through a southern port and a land crossing and the new Turkish move is expected to open other facilities for supplies, officials said. It was expected, however, that Turkey would keep its condition that no soldiers or weapons could enter Iraq through its territory, diplomats said.
Gul also said the bases could be used by peacekeepers. Permission to use the bases would be valid for one year. He said no parliamentary approval was needed for peacekeepers to use Turkish territory.
Any permission to use bases for military operations would still require parliamentary approval.
The announcement came after Foreign Ministry Undersecretary Ugur Ziyal held talks with top U.S. officials in Washington last week to repair relations.
Turkey has also offered to send peacekeepers to Iraq, a request that has so far not drawn a response from the U.S. government, officials said.