Donald Trump hit out Tuesday at a New York judge for extending a gag order preventing the former US president from attacking those involved in his upcoming hush money trial, calling it "election interference".

On Monday, the judge presiding over Trump's trial for allegedly making pre-election payments to a porn star expanded the gag order against him to include comments about family members of the magistrate and Manhattan District Attorney Alvin Bragg.

The move came after the Republican presidential candidate lashed out at Judge Juan Merchan and his daughter in a series of posts on Truth Social.

"I just was informed that another corrupt New York Judge, Juan Merchan, GAGGED me so that I can not talk about the corruption and conflicts taking place in his courtroom," Trump wrote on his Truth Social platform.

"They can talk about me, but I can't talk about them??? That sounds fair, doesn't it?

"This Judge should be recused, and the case should be thrown out.

"ELECTION INTERFERENCE at its worst!"

In his order on Monday, Merchan said Trump's "pattern of attacking family members of presiding jurists and attorneys assigned to his cases serves no legitimate purpose."

"It merely injects fear in those assigned or called to participate in the proceedings, that not only they, but their family members as well, are 'fair game' for defendant's vitriol."

Trump faces charges of falsifying business records for payments made by his lawyer Michael Cohen on the eve of the 2016 presidential election to porn star Stormy Daniels to make sure she did not publicize a sexual encounter.

The case will kick off on April 15 and is the first ever criminal trial of a former president.

Asked by reporters if he would take the witness stand, Trump has said he "would have no problem testifying."

Trump now has four criminal indictments to his name and faces 88 felony counts for a wide variety of alleged criminality.