With that in mind, Osborne said that any deal struck between Labour and the SNP would equal "insecurity", more debt and an "anti-business" agenda.
"We've got a really clear choice in this election between the stability of David Cameron's plan, and the plan is turning around the British economy, and the alternative, which is Ed Miliband-Scottish Nationalists, which is insecurity and job losses for Britain," Osborne told CNBC on Tuesday at an event in Hastings on the south coast of England.
Labour leader, Ed Miliband, has rejected the idea of a formal coalition with the SNP—which led an unsuccessful bid for Scottish independence last year—but has refused to rule out a less formal arrangement.
Read MoreUK election: Battle for center ground heats up
On Monday, SNP leader, Nicola Sturgeon, tried to woo Labour by coming out in support of key Labour tax policies, including the "mansion tax" and a tax on bankers' bonuses.
Conservative Prime Minister David Cameron launched a blistering attack on the notion of a Labour-SNP tie-up on Monday, describing the prospect as a "match made in hell."
Osborne was similarly disdainful on Tuesday.
"Britain has a long-term plan, the jobs are coming, the prosperity is here, the investment is here—with a lot more to do," Osborne told CNBC.
"In this election, let's not put it at risk with the instability of an Ed Miliband-Scottish Nationalist government, anti-business agenda, and more borrowing and more debt," he later added.
With just 16 days to go before polls open, Osborne urged the British public to vote carefully to ensure the SNP remained out of power.
"If you want to stop Ed Miliband and the Scottish Nationalists being in charge—and independent experts now saying that's the only way that Labour can get into office—you have to vote Conservative," Osborne told CNBC.
"If you vote UKIP, that allows Ed Miliband in, if you vote Liberal Democrats, that allows Ed Miliband in. So we are saying the answer to all of these conundrums people have in local constituencies is very simple, which is vote Conservative."
On Monday, Boris Johnson, the Mayor of London and one of the best-known Conservative Party politicians in the country, attacked Miliband and his prospective coalition partner in a Facebook post.
Read MoreUK elections: Is anyone able to form a government?
"Miliband is already the most Left-wing Labour leader since Michael Foot, promoting an agenda that seems to be avowedly hostile to wealth creation and 'predatory' capitalism," Johnson said in a Facebook post.
"The SNP are Lefties on steroids. They want to abandon any attempt to get the deficit under control, and indeed the Treasury has calculated that they would borrow another £148 billion."
—With contribution from CNBC's Catherine Boyle