The US auto safety agency NHTSA wants to meet with 12 major automakers that failed to meet a December 2017 target deadline for completing repairs on the highest-priority vehicles with dangerous Takata air bag inflators, a media report said.

According to Reuters, the National Highway Traffic Safety Administration said it had written letters to automakers including Honda, Toyota, General Motors, Fiat Chrysler Automobiles, Daimler and Ford.

NHTSA told Reuters the 12 automakers had collectively repaired 65% of 20m vehicles in the highest priority groups, leaving about 7m unrepaired.

Nearly 30m US vehicles remain unrepaired in an air bag recall affecting 19 automakers, the report said.

Reuters said the NHTSA had been criticised by some Democratic lawmakers for not doing more to encourage automakers to fix vehicles faster. A US Senate hearing in March also looked at the issue.

Heidi King, deputy NHTSA administrator since September, and under consideration to run the agency, King said in the letter she was "deeply concerned" millions of vehicles in the highest risk category remain unrepaired.

Senator Bill Nelson, the top Democrat on the Commerce Committee, has said he wanted King to work to speed up efforts to get Takata airbags replaced. Of the 22 deaths worldwide, 15 were in the United States. In total, 20 deaths had been reported in Honda vehicles and two in Ford pickup trucks.

"These numbers show that we still have a huge problem with getting these dangerous airbags replaced and off our highways," Nelson said, according to Reuters.