Nikkei states that 17 pieces of chipmaking equipment are inoperable against the 11 reported to be damaged at the original announcement.
Renesas supplies 30 percent of the world's microcontrollers for automotive applications and the fire is expected to make a global supply of semiconductors worse.
The fire took place in the early hours of March 19 and Renesas has said it would take up to a month to resume production at its 300mm wafer fab. However, if it has to replace damaged machines and have them delivered, installed and calibrated the journey back to full production could take several months.
About two-thirds of the Naka output is for the automotive sector.
According to the Nikkei report soot damage from the fire has been found to be worse than previously thought. Renesas reportedly said it plans to report on the extent of the damage by Tuesday March 30.
Related links and articles: