In a statement, the institute said the decision to award a Nobel Prize is final and permanent, citing the statutes of the Nobel Foundation, which do not allow appeals.
The organisation also noted that committees awarding the prizes do not comment on the actions or statements of laureates after receiving awards.
"Once a Nobel Prize is announced, it cannot be revoked, shared or transferred to others," the Norwegian Nobel Committee and the Norwegian Nobel Institute said. "The decision is final and stands for all time."
Earlier in the week Machado, speaking to Fox News presenter Sean Hannity, said presenting the prize to Trump would be an act of gratitude from the Venezuelan people for the removal of Nicolas Maduro, the nation's president, who was captured last week by the United States.
"Did you at any point offer to give him the Nobel Peace Prize?" Hannity asked. "Did that actually happen?"
She responded, "Well, it hasn't happened yet."
Trump, who has long expressed interest in winning the prize and has at times linked it to diplomatic achievements, said he would be honoured to accept the prize if offered by Machado during a planned meeting in Washington next week.
Machado, a former National Assembly member, was barred from running in Venezuela's 2024 general election by authorities aligned with Maduro.
She backed a stand-in candidate who was widely considered to have won the vote, although Maduro claimed victory. Ballot audits by independent observers showed irregularities in the official results.
