Vote Swap, a website launched on Friday, helps Labour and Green voters exchange votes with an aim of ensuring a victory for the Labour party.
Huw Jordan, a co-creator of the website, told BuzzFeed News the website had one key goal around which Labour and Green supporters could join forces, which is "to keep out a Conservative government."
The founders of the website also wanted to use the website to point out what they consider to be flaws with the current voting system.
Jordan explained: "The website is aimed mostly at people who consider themselves to be Labour supporters or Green supporters but understand that because of our terrible first past the post system, their vote may not count, and also to draw attention to the fact that there are a number of constituencies where the vote actually does make a difference."
The first past the post system means that in most constituencies a maximum of two or three parties could realistically win. That rarely includes the Greens.
"So the aim," Jordan continued, "is to get people who are Labour supporters to swap their votes with Green supporters who are in Labour marginals in order to swing some of those marginal seats. And in turn for labour supporters to vote for Green to boost the Greens' national vote."
Last month BuzzFeed News reported that Labour strategists have identified 12 seats the party thinks it could lose due to losing voters to the Greens. The Green party is not necessarily likely to win in these seats but if enough votes transfer to Natalie Bennett's party, Labour could miss out.
The website allows you to enter your postcode or search for your constituency to see how you should vote. We put in Leeds North West, a Labour target seat where the Greens are taking voters.
The problem, however, occurs when you enter in a seat where both Labour and the Greens might win and users are told to vote based on their principles.
And that's something Green party activists have spotted.
@JeremyCliffe @sunny_hundal #greens do not get taken in by this site - it only recommends swaps to benefit Labour - not in Green targets!
But Jordan says that shouldn't put off Green voters as they can still push for a higher national vote.
According to Jordan, "if the Greens gets a high proportion of the national vote, the election result will put forward the argument for proportional representation."
This would mean that parties would be allocated MPs based on the number of votes they receive.