BERLIN, Aug 11 (Reuters) - Germany"s Social Democrats have gained more ground on Angela Merkel"s conservatives ahead of September"s federal election, two opinion polls showed on Wednesday, but they would still need to team up with two other parties to be able to govern. The latest Forsa poll for RTL television put support for the Social Democrats (SPD) at 19%, up 3 points since last week and the best result for the centre-left party since 2018. The SPD is currently junior coalition partner to Merkel"s conservatives. Support for the conservatives slipped 3 points to 23%, the Greens were steady on 20% and the business-friendly Free Democrats (FDP) fell a point to 12%. Merkel, in power since 2005, plans to stand down after the election. The second poll, from Kantar for Focus magazine, put the SPD at 19%, up one point, and the centre-right CDU/CSU bloc at only 22%, down 2 points. The Greens were down one point at 21%. With the statistical margin of error given by Kantar of around 3 percentage points, the survey means that all three parties are roughly neck and neck. The new polls mean that the only possible coalitions would need three parties to work together rather than the current two, potentially making negotiations more protracted. In a hypothetical direct vote for chancellor, the SPD"s candidate Olaf Scholz saw his support in the Forsa poll jump 5 points to 26%, while Armin Laschet, the conservative candidate to succeed Merkel as chancellor, slipped 3 points to just 12%. Laschet has suffered a slump in support after he was seen laughing on a visit to a flood-stricken town. That has prompted some critics to suggest Laschet should renounce his candidacy in favour of Markus Soeder, leader of the Bavarian sister party of Merkel"s Christian Democrats, who the Forsa poll showed would win 40% of support in a direct vote. Support for the Greens" candidate, Annalena Baerbock, slipped 2 points to 16%. Forsa surveyed 2,509 voters between Aug. 3 and 9 for the poll. Kantar surveyed 1,446 voters between Aug. 4 and 10.