The US government has announced a $1.2 billion settlement with Toyota and filed a criminal charge alleging the company defrauded consumers by issuing misleading statements about safety issues.

Attorney General Eric Holder said it is the largest financial penalty of its kind ever imposed on a car company. Under a deferred prosecution agreement, an independent monitor will review policies, practices and procedures at the company.

The action concludes a four-year criminal investigation into the Japanese car maker's disclosure of safety problems, which focused on whether Toyota was forthright in reporting problems related to unintended acceleration troubles.

"Rather than promptly disclosing and correcting safety issues ... Toyota made misleading public statements to consumers and gave inaccurate facts to members of Congress," Mr Holder told a news conference.

Toyota said that at the time of the recalls, "we took full responsibility for any concerns our actions may have caused customers, and we rededicated ourselves to earning their trust," said Christopher P Reynolds, chief legal officer of Toyota Motor North America.

"In the more than four years since these recalls, we have gone back to basics at Toyota to put our customers first."

Toyota said it had "made fundamental changes to become a more responsive and customer-focused organisation, and we are committed to continued improvements".

Starting in 2009, Toyota issued massive recalls, mostly in the US, totalling more than 10 million vehicles for various problems including faulty brakes, gas pedals and floor mats. From 2010 through 2012, Toyota paid fines totalling more than $66 million for delays in reporting unintended acceleration problems.

The National Highway Traffic Safety Administration never found defects in electronics or software in Toyota cars, which had been targeted as a possible cause.