(Adds Colonial response, context, details of the plan)

By Devika Krishna Kumar

NEW YORK, Nov 8 (Reuters) - Colonial Pipeline Co's plan to restore its repaired gasoline line to service after a leak in September does not yet have federal approval, a spokesman for the U.S. regulator told Reuters on Tuesday.

Work on that line had been halted after a fatal explosion last week several miles from the spill site. The blast led to a near week-long shut down of the line, the second shutdown in two months.

Colonial Pipeline restarted the line Sunday - but still is in the process of fixing the original line that leaked in September.

Colonial said on Tuesday it would resume work to remove a bypass it had constructed as a workaround after the spill in order to restart the original gasoline line by mid-November as had been scheduled.

The fuel artery carries 1.3 million barrels of gasoline from the refining hub of the Gulf Coast to the East Coast everyday. The September outage caused severe fuel shortages to millions of Americans, particularly in Southeastern states that do not have access to ports.

The September and October incidents were being investigated separately and a restart plan has not yet been approved by the U.S. Department of Transportation's Pipeline and Hazardous Material Safety Administration (PHMSA), the spokesman for the regulator said.

Colonial previously said a draft restart plan had been submitted to PHMSA. The plan must, among other things, address any findings that require remedial measures to be implemented before the restart.

"We continue to work with PHMSA on the restart plan, which will require their sign-off," Colonial said in an emailed statement to Reuters on Tuesday.

The company said in a notice to shippers earlier in the day that it has cut shipping volumes while it works to restart the section of its gasoline conduit that was damaged after the spill in September - its biggest gasoline leak in nearly two decades.

Operating rates will not be affected after the replacement of the bypass.

"The sections of pipe that will be installed (once the bypass has been removed) have been tested and are in place to expedite the replacement and return to service," a Colonial spokesman told Reuters.

Allocations on the main gasoline line on the biggest refined products system in the United States will be reduced by about 20 percent while the work continues.

(Reporting by Devika Krishna Kumar in New York; Editing by Andrew Hay and Diane Craft)