The promotion was designed to sign people up to its database with the chance to win a £1,000 gift card.
According to a Sky News Habitat's communications team said they had not authorised the messages, but they have confirmed they were not hacked.
"The hashtags were uploaded without Habitat's authorisation by an overenthusiastic intern who did not fully understand the ramifications of his actions. He is no longer associated with Habitat," a spokesman said.
Twitter users accused Habitat of spamming and its mistake was heavily retweeted on the micro blogging service. It was being touted as a case study example of what marketers should not do on Twitter.
The offending tweets have since been removed and Habitat promised to "do better for the Twitter community".
Source: Brand Republic