Toyota‘s president indicated on Wednesday he would not attend a hearing by US lawmakers next week over the automaker’s mass vehicle recalls as the federal administration steps up its investigation into the crisis.

Toyota also said it was also now investigating possible steering problems with the Corolla, the world’s top selling car.

And it announced a range of new measures to boost quality and reassure owners, saying president Akio Toyoda would head a task force to improve quality control and enable the group to respond more quickly to reports of defects.

The Toyota family scion, grandson of the automaker’s founder, who was criticised earlier for his handling of the safety problems, indicated that he had no plan to appear on Capitol Hill on 24 February for one of several planned congressional hearings on the matter.

Instead Toyoda said he would give “maximum support” to his senior executives, including North America chief Yoshimi Inaba, who are due to be grilled by politicians next week.

“I am sure they are well equipped to well respond to the questions and concerns of congressmen,” he told a news conference in Japan, his third this month on the safety issues that have tarnished the company’s once-glowing reputation.

“I think there was some misunderstanding about my plans” to visit the United States, Toyoda said, according to Reuters.

“I have full confidence in the management of Toyota Motor North America, led by Mr Inaba, and I believe he is the best placed to testify,” he said.

Toyoda added that he wanted to focus on internal reform to improve quality management.

Toyoda said, however, that if he was formally invited to appear before Congress he would consider doing so, Kyodo News reported.

Toyoda denied his company had ever covered up safety defects.

“We have not withheld information and we shall not do so in the future,” Toyoda said.

He added his family firm may have grown too fast, neglecting the careful training of staff to ensure quality did not trail behind, Reuters noted.

“Up to now, we had been saying that the rapid expansion was in response to customer needs – that it was inevitable,” Toyoda said.

“The basic rule of the Toyota Production System is to only build as many cars as there is demand for, and we ourselves broke that rule,” he said.

Toyoda said some of the sales during the rapid expansion over the last decade may have been driven artificially by sales financing, and were not based on “real demand”.

President Barack Obama’s transportation secretary Ray LaHood has repeatedly vowed “to hold Toyota’s feet to the fire” to make sure its cars are safe.

Toyota has recalled over 8m vehicles worldwide, more than its entire 2009 global sales, due to the safety problems.

The number of complaints alleging deaths related to unintended acceleration in Toyota vehicles has surged since the company announced on 26 January it was suspending sales and production of eight models in the United States.

The company also faces dozens of lawsuits in the United States alleging Toyota was too slow to act on the problems. Experts say the legal action could potentially cost the company billions of dollars.

According to the NHTSA’s website, 34 deaths allegedly were caused by the problem, including 13 deaths caused by nine accidents between 2005 and 2010 that were reported since late January.

Responding to the agency’s request, Toyota said it took “responsibility to advance vehicle safety seriously and to alert government officials of any safety issue in a timely manner.

“We are reviewing NHTSA’s request and will cooperate to provide all the information they have requested,” it added.

Toyota is also investigating a possible defect in the power steering of its best-selling Corolla model and will recall it if found to be faulty, executive vice president Shinichi Sasaki said.

“If this is a defect, we will start recalls,” he said. “We are in the process of investigating, but the number of complaints is less than 100.”