NEW YORK -- Republican presidential candidate Donald Trump said on Thursday he would establish a government efficiency commission headed by billionaire supporter Elon Musk if he wins the Nov. 5 election, during a wide-ranging speech in which he laid out his economic vision for the country.

Speaking at the New York Economic Club, the former president also pledged to slash corporate tax rates for companies that manufacture domestically, establish "low-tax" zones on federal lands where construction companies would be encouraged to build new homes, and start a sovereign wealth fund.

Trump had been discussing the idea of an efficiency commission with aides for weeks, people with knowledge of those conversations have told Reuters. His Thursday speech, however, was the first time he publicly endorsed the idea.

It was also the first time Trump said Musk had agreed to head the body. Trump did not detail how such a commission would operate, besides saying it would develop a plan to eliminate "fraud and improper payments" within six months of being formed.

"I will create a government efficiency commission tasked with conducting a complete financial and performance audit of the entire federal government," Trump told an audience that included Trump's former treasury secretary, Steve Mnuchin, and financiers Scott Bessent and John Paulson.

Musk said on an Aug. 19 podcast that he had held conversations with the former president about the commission and that he would be interested in serving on it.

"I look forward to serving America if the opportunity arises," the Tesla chief wrote on X on Thursday. "No pay, no title, no recognition is needed."

Politicians have called for separate efficiency commissions before. Republican President Ronald Reagan established a similar body during his 1981-1989 term called the Grace Commission.

Trump's proposal drew a rebuke from Everett Kelley, president of the American Federation of Government Employees, a union representing about 750,000 federal workers. He accused Trump and Musk of wanting to gut the nonpartisan civil service and replace fired workers with allies.

"There's nothing efficient about that," Kelley told Reuters.

Asked by Reuters about Musk heading the proposed government efficiency panel, Paulson said it was "great to have him as an ally. He's a terrific businessman, and I think the government could become much, much more efficient."

Corporate tax cuts, housing on federal lands

During his speech, Trump reiterated his plan to cut the corporate tax rate to 15 percent from 21 percent, but only for companies that manufacture domestically. He also said he would open up federal land to homebuilding in a bid to drive down housing costs. These new housing zones would be "low-tax" and "low-regulation," Trump said, without elaborating.

While Trump had already said he wanted to cut the corporate rate to 15 percent, he had not previously tied that rate to keeping manufacturing inside the country.

Trump also called for creating a sovereign wealth fund, in part to fund major infrastructure projects. He added that he would rescind unspent funds related to the 2022 Inflation Reduction Act, one of Biden's signature legislative accomplishments. And Trump said he would "issue a national emergency declaration" in a bid to help new energy projects more easily clear bureaucratic hurdles.

Trump said he would ban mortgages for migrants living illegally in California, after asserting without evidence that they were driving up housing costs. He did not provide specifics on how he would enact such a ban. Banks can provide mortgages to migrants in the country illegally, but do so infrequently.

Trump's housing affordability plan differs drastically from that of Vice President Kamala Harris, the Democratic nominee, who has proposed creating a $25,000 credit for first-time homebuyers.

Harris' plan has been criticized by Republicans and some economists who say the credit will drive up housing prices. Trump's plan to develop federal lands, on the other hand, could draw the ire of environmentalists, and it is unclear how much housing demand there would be in the rural areas where most federal land is located.

Responding to a question from the audience, Trump said he would apply punitive economic sanctions to other countries only sparingly, so as not to threaten the dollar's status as the global reserve currency, a position at odds with his record during his time in office.

During Trump's 2017-2021 term, sanctions were a go-to foreign policy tool, and some advisers have advocated expanding sanctions against Iran and Russia.

Harris policy adviser Brian Nelson said Trump's economic agenda would "explode the national debt," while driving up inflation and killing jobs.

Trump is seen as a more competent steward of the economy by more voters. But his advantage over Harris on the issue is rapidly eroding, surveys show. Trump had an 11-percentage-point advantage on the economy in July, but that dropped to a 3-point lead in August, Reuters/Ipsos polling showed.

Many economists believe the economic policies sketched out by Trump on the campaign trail will lower growth and drive inflation higher. But they also note that in order to implement much of his policy agenda, Republicans need to retain control of the House of Representatives and seize the Senate from Democrats.