Instead of the party's usual page, readers were greeted with a black page and red lettering across the centre with the group's name and a prophecy from the Koran that describes Islam conquering various lands to bring about the Day of Judgment.
No reason is given for the attack on the page.
A spokesperson for the Bloc also says the party received no warning or reason for why it may have been targeted.
The Bloc also says the party has notified the "appropriate authorities" and it is working to regain control of the page. Shortly after midday, the black and red screen was replaced by a simply message in French that said the site was under construction.
Last week, the Bloc courted controversy when it sent out a tweet criticizing the NDP for supporting the right of Muslim women to wear the niqab during citizenship ceremonies.
In it, the Bloc shows the inside of the House of Commons through cut-out eye-holes, presumably to represent someone looking through a niqab.
It then asks if people will have to cover their faces to vote for the NDP.
United Islamic Cyber Force claimed credit this past January when a number of France-based websites found themselves under similar attacks after having, according the the hackers, insulted Islam.
The pages in question had indicated support for Charlie Hebdo after the deadly attack on its office in Paris.