The US National Transportation Safety Board is "probably weeks away" from completing its probe into causes of a battery fire on the Boeing 787 Dreamliner, but will share its latest information tomorrow.

NTSB chairman Deborah Hersman said the NTSB "will talk about special conditions that were put into effect at the time when the Dreamliner was certified".

She was speaking to reporters at a breakfast briefing hosted by the Christian Science Monitor.

"In essence what happens when an aircraft is certified, it basically gets locked into the standards that are in existence at the time. So the question ... is whether or not as time goes on through the life of the aircraft, do they fly with new standards?," Ms Hersman said.