Berlin, Sep 21 (IANS): Chancellor Angela Merkel's conservative bloc is in a leading position but it is not definite that the current governing coalition would continue to hold on to power, an exit poll said ahead of Sunday's election in Germany.

With her successful stewardship of Europe's largest economy and her adherence to principles in handling the euro zone debt crisis, Merkel won her Christian Democratic Union (CDU) and its Bavarian sister party Christian Social Union (CSU) a high approval rate, Xinhua reported.

In a poll released by Forsa institute Friday, the CDU/CSU union garnered 40 percent support, 14 points ahead of its main rival, the Social Democratic Party (SPD).

But Merkel's pro-business partner Free Democratic Party (FDP) attained five percent, just enough to meet the threshold to enter parliament. The SPD's preferred ally, the Greens, gained a support rate of 10 percent. The Left, another party which could enter the legislature, netted nine percent.

In Germany, a ruling party or coalition needs a majority of seats in the parliament. The Forsa poll indicates that the Sunday election would run neck and neck.

Merkel's conservative bloc may be forced to form a "grand coalition" with the centre-left SPD, should the FDP fail to get a support rate of five percent.

The FDP has been wiggling around the five percent hurdle for months. It became pressing when the party failed to win any seat in the Bavarian parliament last Sunday though the CSU captured an absolute majority of 48.3 percent.

"It is a wake up call," said FDP leader Philipp Roesler.

For the coming federal election, FDP has called for supporters of CDU/CSU to give their second votes to the FDP in order to continue the current governing coalition.

German voters could cast two votes, the first for a specific candidate to represent their constituencies, the second for a party. The second vote would determine seat shares of parties in parliament.

The tactical proposal, however, was rejected by CDU officials.

"We have no vote to give away," said Merkel at a rally this week.

Another potential game changer in the election is the Alternative for Germany (AfD) which was founded early this year.

The anti-euro party has earned a support rate of around four percent.

The party says that euro has proved to be a failure and wanted countries to be allowed to leave the euro zone.

A poll by INSA institute Thursday even showed that it garnered five percent, meaning the party was likely to enter the legislature.

If that happens in Sunday's election, there would be six parties in parliament, more seats would be taken away from the CDU/CSU union.

It would be more difficult for the centre-right coalition to win a majority in parliament, then a "grand coalition" of Merkel's union and the SPD would seem inevitable despite the fact that Merkel insisted Wednesday that she would continue her coalition with FDP even if it has only a one-seat majority.

Analysts believe that Merkel would retain her post, either in the current centre-right coalition or in a "grand coalition" with the SPD. Her main rival, SPD chancellor candidate Peer Steinbrueck, has a much weaker popularity rating among German voters.