The co-leaders of the Social Democrats have announced they are stepping down.

Catherine Murphy and Róisín Shortall confirmed they are resigning with immediate effect, and a leadership contest will take place soon.

The two TDs also said they will continue to represent their constituencies, and they both intend to stand in the next general election.

Deputy Shortall said they were put under no pressure to step down.

"Catherine and I have decided that the time is right now to hand over the leadership reigns of the party to the next generation of Social Democrats," she said.

"We have, therefore, notified our national exectuive that we are stepping down as joint leaders.

"We have requested that they make arrangement for the election of a new leader."

Deputy Shortall said whoever succeeds them will need time to get established.

"We want to ensure that whoever succeeds us as party leader would have time to bed in and get established, and get to travel the country and meet the various branches and all of that," she said.

Deputy Murphy said time was the main reason for their decision.

"That is the absolute main reason - because of the time," she said.

"I know people would like there to be other reasons, but there isn't," she added.