US district judge Richard Leon denied the National Trust’s bid for a temporary restraining order, saying it failed to show “irreparable harm” at this stage in its lawsuit, but said the government must be prepared to undo any below-ground construction that dictates a specific design.

Since his January return to office, the Republican president has installed gold decorations throughout the Oval Office and paved over the lawn of the Rose Garden to create a patio resembling the setting at his Mar-a-Lago estate in Florida.

The White House and preservation group did not immediately respond to requests for comment.

The 90,000-square-foot (8,360sqm) ballroom Trump envisions would dwarf those renovations. In comments at a Hanukkah reception at the White House on Tuesday night, he said his ballroom would cost US$400 million, up from an earlier US$300 million estimate.

“President Trump has full legal authority to modernise, renovate, and beautify the White House – just like all of his predecessors did,” White House spokesman Davis Ingle said in a statement on Tuesday.

The government said in court papers that the design was evolving and that above-ground construction on the ballroom, which is being funded through private donations, would not begin before April. The judge scheduled a hearing in January to again consider pausing the project as the case proceeds.

“At yesterday’s hearing, the Government represented that nothing about the ballroom has been finalised, including its size and scale,” Leon said in Wednesday’s order. “Based on those representations, there is no sufficiently imminent risk of irreparable aesthetic harm warranting a temporary restraining order halting construction over the next fourteen days.”

The preservation group’s lawsuit said Trump tore down the East Wing and started work on the ballroom without first gathering public input and that he ignored statutes requiring consultation with the National Capital Planning Commission and the Commission of Fine Arts.