By Karen Freifeld and Sarah N. Lynch

NEW YORK (Reuters) -Former President Donald Trump's lawyers resisted revealing whether he declassified materials seized in an August FBI search of his Florida home as the U.S. judge appointed to review the documents planned his first conference on the matter on Tuesday.

Judge Raymond Dearie on Monday circulated a draft plan to both sides that sought details on documents Trump allegedly declassified, as he claimed publicly and without evidence, though his lawyers have not asserted that in court filings.

In a letter filed ahead of Tuesday's hearing, Trump's lawyers argued it is not time and would force him to reveal a defense to any subsequent indictment - an acknowledgement that the investigation could lead to criminal charges.

Dearie, a senior federal judge in Brooklyn, was selected as an independent arbiter known as a special master. He will help decide which of the more than 11,000 documents seized in the August 8 search of Trump's Mar-a-Lago home should be kept from the Justice Department's criminal investigation into the alleged mishandling of the documents.

Dearie will recommend to U.S. District Judge Aileen Cannon which documents may fall under attorney-client privilege or an assertion of executive privilege, which allows a president to withhold certain documents or information.

It is unclear whether the review would go forward as instructed by Cannon, the Florida judge appointed to the bench by Trump in 2020 who ordered the review.

Trump is under investigation for retaining government records, some marked as highly classified, at the resort in Palm Beach, his home after leaving office in January 2021. He has denied wrongdoing, and said without providing evidence that he believes the investigation is a partisan attack.

The Justice Department on Friday appealed a portion of Cannon's ruling, seeking to stay the review of roughly 100 documents with classified markings and the judge's restricting FBI access to them.

Federal prosecutors said the special master review ordered by the judge would hinder the government from addressing national security risks and force the disclosure of "highly sensitive materials."

On Tuesday, Trump's legal team filed its response to the Atlanta-based 11th U.S. Circuit Court of Appeals, opposing the government's request and calling the Justice Department's investigation "unprecedented and misguided."

In their 40-page filing, Trump's attorneys said the court should not take the Justice Department at its word that the roughly 100 documents in question are in fact still classified, and said the special master should be permitted to review them as a step towards "restoring order from chaos."

In Cannon's order appointing Dearie as special master, she asked him to conclude his review by the end of November. She instructed him to prioritize the documents marked classified, though her process calls for Trump's counsel to review the documents, and Trump's lawyers may not have the necessary security clearance.

The Justice Department has described the special master process as unnecessary, as it has already conducted its own attorney-client privilege review and set aside about 500 pages that could qualify. It opposes an executive privilege review, saying any such assertion over the records would fail.

The August FBI search came after Trump left office with documents that belong to the government and did not return them, despite numerous requests by the government and a subpoena.

It is still unclear whether the government has all the records. The Justice Department has said some classified material still could be missing after the FBI recovered empty folders with classification markings from Mar-a-Lago.

(Reporting by Karen Freifeld, additional reporting by Sarah N. Lynch; editing by Scott Malone, Will Dunham, David Gregorio and Chizu Nomiyama)