Foreign Investment Security Improvement Act of 2006

Foreign Investment Security Improvement Act of 2006 - Directs the President (or the President's designee) to investigate, under the Defense Production Act of 1950, the acquisition by Dubai Ports World (DP World), an entity owned or controlled by the Emirate of Dubai, of the Peninsular and Oriental (P&O) Steam Navigation Company, a national of the United Kingdom. Requires such investigation to be completed within 45 days after enactment of this Act.

Directs the President to suspend any decision, under provisions of the Defense Production Act of 1950 permitting the President to stop the acquisition because it will impair national security, with respect to such acquisition made before the completion of the investigation, including any decision made before enactment of this Act.

Specifies requirements for the investigation. Requires the Secretary of Homeland Security to provide information for the investigation, including: (1) relevant information on DP World from the Automated Targeting System maintained by U.S. Customs and Border Protection; and (2) port assessments at foreign seaports where DP World operates.

Requires the President to: (1) report to Congress within 15 days after completion of the investigation; and (2) provide certain Members of Congress a detailed briefing on the contents of the report.

Requires the President to take action necessary to prohibit the acquisition if the President does not stop the acquisition under the provisions of the Defense Production Act of 1950 permitting the President to stop the acquisition because it will impair national security if a joint resolution of disapproval is enacted into law within 30 days after Congress receives a report from the President that an acquisition will not be stopped. Requires, if such acquisition has been already been completed, the President to direct the Attorney General to seek divestment or other appropriate relief in US district courts.