UPDATE 3-US: GM bankruptcy would take at least 60-90 days

* U.S. expects at least 35 pct approval of bond offer

* Obama expected to discuss GM on Monday

* U.S. plans to extend up to $30 bln in new aid to GM

* Opel a matter for GM/German gov't to work out

(Obama officials to visit midwest; Opel)

By John Crawley

WASHINGTON, May 28 (Reuters) - The Obama administration estimates that a General Motors Corp GM.N bankruptcy would take at least 60 to 90 days and perhaps longer to complete, a senior official said on Thursday.

The official, who spoke on the condition of anonymity because he was not authorized to discuss the matter publicly, would not confirm a specific bankruptcy scenario, but the government's deadline for any filing is on Monday.

President Barack Obama is expected to discuss the automaker's restructuring at that time, the White House said. On April 30, Obama announced that Chrysler was seeking Chapter 11 protection.

The administration is also planning an extraordinary offensive beginning on June 2 of sending senior officials to Midwest communities most affected by job losses and other aspects of GM and Chrysler bankruptcies. Eight Cabinet secretaries and other top officials will visit Ohio, Michigan, Indiana and Wisconsin to discuss federal efforts to help workers.

Chrysler, GM's smaller rival, is on the verge of stepping out of court protection. GM and Chrysler are operating under the direction of a White House/Treasury Department task force, which has provided more than $36 billion in bailout assistance to the automakers and their affiliated finance companies.

The official said GM, a publicly traded company with a global footprint, is more complex than privately held Chrysler and would take longer to reorganize in court, even under the expedited strategy the government has mapped out.

"I think the 60-to-90-day time frame is a better time frame to establish than something that looks like Chrysler," the official said.

GM would be a private company for some time, under the government's restructuring road map, the official said.

A GM spokesman declined comment on the scope of any bankruptcy.

The administration official also said that total new U.S. government aid to GM, including any debtor financing in bankruptcy, would top $30 billion. The Canadian government would also offer some $9 billion.