More than €12 million has been spent on the probe to find the missing girl, who vanished from the family's holiday apartment in Praia da Luz in Portugal in May 2007, aged three.
Funding for the investigation, known as Operation Grange, had been agreed up until the end of September.
But the extra funds were granted by the Home Office following an application by the Metropolitan Police.
A Home Office spokesman said: "Following an application from the Metropolitan Police, the Home Office has confirmed funding for Operation Grange until the end of March 2018.
"As with all applications, the resources required are reviewed regularly and careful consideration is given before any funding is allocated."
It is understood the number of officers working on the investigation will remain the same.
Madeleine's parents Kate and Gerry McCann, of Rothley, Leicestershire, have vowed never to give up hope of finding their daughter.
Since 2011, the Met Police have been assisting with the search for clues about what happened to Madeleine, with officers visiting the holiday resort in 2014.
In March, the Home Office granted officers £85,000 to cover "operational costs" to continue with the investigation, between April and September this year.
Whats the Home Office and government playing at £175,000 for Operation Grange enough is enough....spend the money on the living, harsh I know but come on they haven't come up with anything yet!!!!!!
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By carole york from UK on 01 Oct 2017, 10:38
Disgusting waste of money considering that the parents were responsible for her disappearance by abandoning her and her siblings.
By G Neves from Algarve on 03 Oct 2017, 12:08