A US government-appointed "pay czar" on Friday extended limits on pay and perks at four bailed-out US companies - including an automaker - to a second tier of executives.

Kenneth Feinberg, the special master overseeing pay at firms aided by the Troubled Asset Relief Programme (TARP), said the new decision would cover the 26th to 100th most highly paid executives at the firms, after a previous ruling on the top 25.

The limits, including a cap in cash salaries of US$500,000 annually in most cases, would apply to General Motors and GMAC, the former finance arm of GM, insurer AIG and bank Citigroup, firms that received "exceptional" government aid.

Bank of America, which repaid $45bn in TARP funds this week, was exempt from the ruling, AFP reported.

Additionally, Chrysler and Chrysler Financial were exempted because executives received less than the "safe harbour" amount, with one exception.

The ruling said cash salaries should be limited to $500,000 but said some higher amounts would be allowed "in exceptional cases as specifically certified by the company's independent compensation committee."

It said the companies have so far identified "about 12" exceptional cases, the news agency added.