WASHINGTON (Reuters) -The massive U.S. tax and budget bill being finalized by Congress cannot pass a provision that automatically enables offshore oil and gas projects to skip over the federal environmental review process unless it gets at least 60 Senate votes, the body's parliamentarian said on Monday.

This is among the latest provisions that have been struck by Senate parliamentarian Elizabeth MacDonough, whose role is to ensure that lawmakers follow proper legislative procedure, such as requiring 60 out of 100 Senate votes instead of a simple majority.

The parliamentarian is combing through the budget megabill to ensure it complies with the decades-old Byrd Rule, which prohibits provisions that are "extraneous" to the federal budget in large pieces of legislation.

The list of problematic provisions flagged by MacDonough adds additional hurdles as Senate Majority Leader John Thune, House Speaker Mike Johnson and administration officials are pressing Republican lawmakers to pass the OBBB Act so President Donald Trump can sign it into law before the July 4 U.S. Independence Day holiday.

The parliamentarian has said that provisions in OBBB that deem offshore oil and gas projects as automatically compliant with the National Environmental Policy Act require would require a higher vote threshold.

The parliamentarian also said that a controversial provision championed by Senator Mike Lee that would authorize the sale of millions of acres of Bureau of Land Management and U.S. Forest Service lands should be removed from the bill, as well as a provision that greenlights the construction of a mining road in Alaska.

She also flagged a provision that enabled gas exporters to pay to allow their projects to be deemed "in the national interest," a time-consuming determination usually made by the federal government; a section that requires oil and gas leases to be issued to successful bidders within 90 days and one that removes the ability of the Interior secretary to reduce fees for renewable energy on federal lands as needing to face a higher vote threshold.

Thune has said repeatedly that he will not overrule the parliamentarian. On Monday, he told reporters that the process is "something we have to go through."

"They're working through it. And in some cases, as things are flagged, we're making counter offers," he said.

Senator John Cornyn also told reporters on Monday: "We don't know what the end-product is going to look like. But we're going to keep trying to maximize what we can do using reconciliation."

The parliamentarian said last week that a proposed rollback in the OBBB of the Environmental Protection Agency's new emissions limits for medium- and heavy-duty vehicles like delivery trucks and a provision enabling companies to pay to opt out of the environmental permit review process can't pass without 60 votes.

Thune aims to begin Senate action by the middle of this week and complete passage by the weekend, sending the bill back to the House for final approval.

Senate Democrats said they will continue to ensure that the OBBB gets thorough scrutiny.

"Democrats will not stand idly by while Republicans attempt to circumvent the rules of reconciliation in order to sell off public lands to fund tax breaks for billionaires," said Senator Jeff Merkeley, top Democrat on the Senate budget committee.