In a second amended complaint filed in Manhattan federal court, Trump's lawyers argued that the subpoena was "wildly overbroad" and was issued in "bad faith" and amounts to "harassment."

Trump, who is seeking re-election on November 3, has fought to keep his tax returns secret.

Manhattan District Attorney Cyrus Vance subpoenaed Trump's accounting firm for eight years of his business and personal returns and other documents as part of a criminal investigation involving Trump and the Trump Organisation, his family's real estate business.

Carey Dunne, general counsel for Vance, on July 16 warned US District Court Judge Victor Marrero against allowing Trump to delay long enough to get beyond statutes of limitations.

Trump filed suit last year to block Vance from getting his records, arguing the subpoena was invalid. On July 9, the Supreme Court in a 7-2 vote rejected his argument that he was immune from state criminal probes while in the White House. .

The high court said, however, that Trump could challenge the subpoena on other grounds.

Vance's office noted in a filing this month that the judge had previously rejected Trump's claims that the subpoena was in bad faith, intended to harass or impair his presidential duties.

Vance's investigation began after reports that Trump's former lawyer Michael Cohen paid pornographic film actress Stormy Daniels $US130,000 ($A182,915) to buy her silence before the 2016 election about sexual encounters with Trump, which he has denied.

Even if Vance prevails, grand jury secrecy rules make it unlikely Trump's financial records will become public soon. But that could change if charges are filed against other defendants.

Australian Associated Press