Jesse Benton said the agreement calls for the libertarian congressman from Texas to get 17 additional delegates from Louisiana, as well as three more delegates and two alternates from Massachusetts, The New York Times reported.
The status of delegates from Main was still up in the air, the newspaper said, but Benton said there was a proposal to split that state's delegates between Paul and Romney.
The Times said a Republican National Committee official confirmed the deal.
The Paul campaign also has had influence as the party developed its platform, the Times said, with a plank calling for an audit of the Federal Reserve.
The Times noted Paul is not on the roster of speakers at the GOP national convention next week in Tampa, Fla., though his son, U.S. Sen. Rand Paul of Kentucky, is.
The delegate deal headed off a potential political brouhaha at the convention. The Republican National Committee had concerns Paul supporters from at least six states would disrupt the convention, where Romney is to be formally named the GOP's presidential nominee.
The Portland (Maine) Press Herald had reported earlier the committee had told 20 Maine delegates who support Ron Paul they may not be seated. Republican Maine Gov. Paul LePage threatened to boycott the convention, which starts Monday, if those elected delegates are not seated.
The committee had said Massachusetts and Louisiana Paul delegates would also not be seated, Examiner.com reported.
Ron Paul ended active campaigning May 14 to focus on state delegate-selection conventions.
He failed July 14 to win a plurality of delegates at the final state Republican convention in Nebraska, ending his ability to ensure a speaking spot at the national convention.
The threat by a Paul campaign attorney Monday that Paul supporters from across the country would withhold their votes from Romney followed an Aug. 10 decision by the contests committee that procedures used at the chaotic and sometimes violent Oklahoma Republican Convention May 11-12 to select 25 delegates and alternatives to the convention out of a total of 43 were appropriate.
Paul supporters, some claiming to have been physically attacked at the convention by Romney supporters, alleged many party and parliamentary rules, as well as state law, were not followed.
GOP Oklahoma Gov. Mary Fallin was booed at the convention when she said the party's single goal was to elect Romney as president.
Romney, a former governor of Massachusetts, finished second in Oklahoma's March 6 presidential primary, losing to former U.S. Sen. Rick Santorum of Pennsylvania. Paul won no delegates in the vote.
At one point during a challenging moment at the convention, the overhead lights were turned off and a room partition was moved across the room, isolating many attendees from the rest of the body, video aired by KFOR-TV, Oklahoma City, indicated.
The Paul attorney's threat received a cold response from a high-level convention official.
"That this lawyer turned a rules challenge into political blackmail was thuggish and certainly not the way to restore the first principles of this republic, which is the professed aim of the Ron Paul revolution," convention Vice Chairman Solomon Yue told The Washington Times.
Oklahoma GOP Chairman Matt Parnell revealed the threat during a live Times webcast that featured Parnell and RNC Chairman Reince Priebus as guests.
The threat would have little effect on the Nov. 6 presidential election's outcome in Oklahoma, which is one of the strongest Republican states in the union, but could tip the balance in swing states such as Colorado and New Hampshire, which have concentrations of "Paulites," the Times said.