WASHINGTON (Reuters) - U.S. President Donald Trump met with business leaders on Wednesday including Tesla Inc Chief Executive Elon Musk and real estate developers, as the administration seeks partnerships with the private sector to boost infrastructure spending.

FILE PHOTO: Tesla Chief Executive, Elon Musk enters the lobby of Trump Tower in Manhattan, New York, U.S., January 6, 2017. REUTERS/Shannon Stapleton/File Photo

During his presidential campaign, Trump said he would push for a $1 trillion infrastructure program to rebuild roads, bridges, airports and other public works projects, but he has not presented a specific plan.

White House spokesman Sean Spicer said “strong public-private partnerships” would be key to rebuilding the nation’s roads, bridges and airports.

“Infrastructure used to be a point of American pride, but now an overbearing, ineffective regulatory system can keep projects in limbo for years,” Spicer said. “The government has wasted too much of the taxpayers’ money on inefficient and misguided projects.”

The White House sees infrastructure as a potential large job creator but officials have said the federal government cannot shoulder the entire burden. The administration is looking at toll roads, tax credits and other ways to spur private investment.

Major real estate and private equity executives attended the meeting, including developer Richard LeFrak, Vornado Realty Trust Chief Executive Officer Steve Roth, and Apollo Global Management co-founder Josh Harris, the White House said.

LeFrak and Roth have been tapped to lead an infrastructure council that Trump plans to create, a spokesman for LeFrak had previously said.

The lunch with the CEOs follows his meeting on Tuesday with AFL-CIO union President Rich Trumka to talk infrastructure and other issues. The White House held a meeting of 15 federal agencies last Thursday to begin work on the administration’s infrastructure plan.

Last month, Trump touted the infrastructure plan in an address to Congress.

“To launch our national rebuilding,” he said, “I will be asking Congress to approve legislation that produces a $1 trillion investment in infrastructure of the United States - financed through both public and private capital - creating millions of new jobs.”

Edward Mortimer, a transportation expert at the U.S. Chamber of Commerce, told a Senate panel on Wednesday that without action, the federal highway trust fund would face a serious shortfall starting in 2020, and policymakers would need to come up with $150 billion over six years to maintain current spending.

“This shortfall will likely result in significant uncertainty, with states possibly delaying major transportation projects,” he said.

Wednesday’s meeting included Vice President Mike Pence, Transportation Secretary Elaine Chao, Energy Secretary Rick Perry and Environmental Protection Agency chief Scott Pruitt, as well as General Atlantic CEO Bill Ford, McKinsey & Co partner Tyler Duvall and Nature Conservancy Managing Director Lynn Scarlett, the White House said.

Scarlett said in a statement that any infrastructure package should include “natural” solutions such as reefs, dunes and wetlands. Other participants in the meeting did not comment or respond to requests for comment.

The American Society of Civil Engineers has graded U.S. infrastructure at D+ and estimated the country needs to invest $3.6 trillion by 2020.

In January, Trump signed an executive order aimed at expediting environmental reviews and approvals for all infrastructure projects, especially high-priority projects such as improving the U.S. electric grid and telecommunications systems and repairing and upgrading “critical” port facilities, airports, pipelines, bridges, and highways.