Vanuatu President Baldwin Lonsdale has revoked the pardon of 14 MPs issued last weekend by the acting president, Marcellino Pipite.
Mr Pipite, who is the speaker, pardoned himself and 13 other MPs.
One MP, Willie Jimmy, had pleaded guilty and was not pardoned.
Father Lonsdale was out of the country last weekend and, on his return, said Mr Pipite had acted unlawfully and promised action.
Our correspondent said the president made a decision yesterday, and it was announced in Port Vila this morning.
Father Lonsdale cited constitutional obligations on leaders to conduct themselves in such a way that avoided conflicts of interest, compromising official duties, demeaning the office, allowing their integrity to be called into question, or endangering or diminishing respect for - or confidence in - the integrity of Vanuatu's government.
He said Mr Pipite infringed all of these obligations, making the revocation necessary.
The Supreme Court is due to sentence the MPs next Thursday.
Vanuatu march still on despite Presidents revoking pardons
The group, Vanuatu Women Against Crime and Corruption, still plans to go ahead with its planned march in Port Vila on Monday.
It had initially focussed on controversial pardoning of 14 MPs after they had been convicted of giving and receiving corrupt payments.
With that pardon now revoked the march organiser, Jenny Ligo, says they are keen to march to show their solidarity for President Lonsdale's action.
"This is to demonstrate that we also do not want to see these illegal activities happening in Vanuatu, so I think that is the most important thing for women who live in Vila to show physically our demonstration on what has happened."
Ms Ligo says the group has police approval for the march on Monday but are waiting for the green light from the government.