Philippine security forces said Wednesday they had replaced Vice President Sara Duterte's bodyguards, days after the justice department launched a probe into her alleged death threat against President Ferdinand Marcos.

But the decision to swap out Duterte's security detail, a mix of soldiers and police officers, was related to a separate investigation, a police spokeswoman and the country's military chief told reporters.

National police spokeswoman Colonel Jean Fajardo said the force had asked prosecutors to file assault charges against the vice president and members of her detail for allegedly interfering in the transfer of her detained chief of staff.

A police doctor "was pushed by the head of security" of Duterte and "we cannot let this pass", Fajardo told journalists.

Duterte brushed aside the police complaint, telling reporters the allegations against her and her bodyguards "do not hold water".

In a separate press conference, General Romeo Brawner confirmed that soldiers guarding Duterte had been removed from her detail over an unspecified police probe.

The news follows the justice department calling Duterte the "self-confessed mastermind" of a plot to assassinate Marcos, as it issued a subpoena Monday demanding she appear at a formal inquiry.

In a Saturday press conference, Duterte said she had instructed someone to kill Marcos, his wife Liza Araneta-Marcos and cousin Martin Romualdez if an alleged plot to assassinate her was successful.

"If I die, don't stop until you have killed them," she claimed to have said, later denying her remarks constituted a death threat.

Her Saturday plot comments came shortly after House of Representatives officials threatened to transfer her chief of staff from the lower chamber's detention center to a correctional facility. 

Zuleika Lopez has been held for contempt since November 20, when she was cited for allegedly interfering in a probe into Duterte's finances.

The Marcos-Duterte alliance that swept to power in 2022 has collapsed spectacularly in the lead-up to next year's mid-term elections.

Duterte, daughter of former president Rodrigo Duterte, remains his constitutional successor should he be unable to finish his six-year term.

But she is currently facing an investigation in the Romualdez-led House of Representatives over her alleged misuse of millions of dollars in government funds.

Both Romualdez and Duterte are widely expected to run for president in 2028.

Duterte said Wednesday the Marcos camp could try to impeach her.

"They want to remove me from my post. They can try and we'll see," she said.