D.C. Mayor Vincent Gray helped to announce proposed campaign finance reforms Tuesday August 28, 2012 in Washington, D.C. at the Wilson Building. (Katherine Frey/THE WASHINGTON POST)

D.C. Mayor Vincent C. Gray proposed new restrictions on campaign donations on Tuesday, along with additional reporting requirements, saying more rules are needed to scuttle the influence of lobbyists and contractors on District politics.

Outlining proposals he wants to be the centerpiece of the D.C. Council agenda when members return next month from summer recess, Gray (D) seeks to curb political donations from anyone with a city contract of $250,000 or more, prohibit lobbyists from bundling contributions, and ban corporations from donating through various linked entities.

Gray’s proposal, which has not been drafted into legislation, would also require that all campaign donations within 30 days of an election be disclosed within 24 hours.

“It’s a very high priority,” Gray said of his campaign finance proposals. “It’s one of the most important questions we face at this stage.”

But Gray, weighed down by a continuing federal investigation into his fundraising and campaign spending, has largely left the heavy lifting for the legislation to Attorney General Irvin B. Nathan. Earlier this year, as the federal probe into Gray’s campaign intensified, he tasked Nathan with putting together a series of reforms.

After consulting with staff members, advocates and ethics experts, Nathan said he drafted proposals that would address “even the appearance of corruption” or a “pay-to-play culture.”

“The mayor asked me to propose a bold, comprehensive and systematic shift in thinking in our campaign finance laws,” Nathan said. “The goal is to assure going forward our citizens will have full confidence in our elected officials.”

The proposal comes as a group of progressive activists struggles to convince the D.C. Board of Elections that they succeeded in forcing a November initiative that would ban corporations from donating to local campaigns.

The board ruled this month that the group, D.C. Public Trust, failed to turn in enough valid signatures to get the initiative on the ballot. The group filed a court challenge, contending that the board miscounted.

But the board defended its decision Tuesday, saying in a court filing the group did not understand the board’s tallying system. A hearing is scheduled for Thursday.

Nathan is not backing a complete ban on corporate donations, arguing that such a policy could land the District in court.

Instead, Nathan said he crafted proposals he thinks will address the campaign finance controversies that have swirled around D.C. officials, including allegations that city contractor Jeffrey E. Thompson orchestrated straw donations to Gray and several council members.

Nathan also wants to require organizations to disclose the sources of all donations, as candidates are required to do in regular campaign finance reports.

But Nathan wants even more disclosure for candidates within 30 days of an election. Those contributions and expenditures would be uploaded on the office’s Web site for public review.

In another proposal that could reshape campaign fundraising in the District, the administration wants to restrict contributions from limited liability corporations. Under current rules, donations made by LLCs cannot be counted against contribution limits on their owners.

Nathan said the proposal would also prohibit registered lobbyists from soliciting or transmitting contributions from others, preventing them from “bundling” donations to favored elected officials.

And to curb the use of straw donations, Nathan recommended that money-order contributions of more than $25 be outlawed.

Craig Holman, a lobbyist for the consumer advocacy group Public Citizen, said in a statement that if approved, the District would have among the strongest campaign finance laws in the country.

But Gray’s proposals must clear the D.C. Council, where members will likely propose their own ideas for reforming campaign rules.

Council member Muriel Bowser (D-Ward 4), chairwoman of the Government Reform Committee, said the council “will be moving” on the issue this fall but that she had not reviewed Gray’s proposals.

Mike DeBonis contributed to this report.