Berlin  - German Economics Minister Michael Glos said late Sunday he would submit a formal resignation request to Chancellor Angela Merkel on Monday, but confusion over his replacement remained.

After a weekend of frenzied activity within his Christian Social Union (CSU), two contenders for Glos' post emerged Sunday evening. The issue was likely to be clarified following a high-level CSU meeting Monday.

Officials involved in the discussions told Deutsche Presse-Agentur dpa late Sunday that the choice was between CSU Secretary General Karl-Theodor zu Guttenberg, 37, and Bavarian Finance Minister Georg Fahrenschon, 41.

Munich newspaper Abendzeitung reported earlier Sunday that Merkel had agreed to the choice of Guttenberg as a successor to Glos, 64, who on Saturday announced his intention to leave the cabinet.

Guttenberg was picked by CSU chairman Horst Seehofer, who initially rejected Glos' resignation bid and told him he would have to remain in office until after the September 27 general election.

The CSU is the Bavarian sister party of Merkel's Christian Democrats (CDU).

In a resignation letter to Seehofer, Glos cited his age and the need for the CSU, after disappointing state election results last September, to renew itself ahead of the national polls.

Sources within the CSU said the minister's poor relations with Seehofer apparently prompted him to write the letter.

Formally, Merkel is responsible for cabinet appointments, but in line with tradition, the parties in the ruling coalition propose replacements for their own members who leave the government.

Glos has headed the economics ministry since November 2005 when the CDU and CSU took office in a grand coalition with the centre-left Social Democrats (SPD).

The CSU lost its absolute majority in Bavarian state elections last September and was forced to seek a coalition with the business- oriented Free Democrats (FDP).

Seehofer took over the party leadership after the debacle and was also appointed Bavarian premier. He later chose Guttenberg to be the party's secretary general.

Guttenberg was elected in 2002 as a member of parliament in Berlin and rose to become the CSU's spokesman there on disarmament and arms control.

A member of the CSU since 1970, Glos had an unhappy time heading the economics ministry and was often in the shadow of the popular Finance Minister Peer Steinbrueck. He indicated recently that he was growing tired of his job.

Glos' decision to quit comes at a time when Germany is struggling to come to terms with a biting recession that has seen growth plummet, unemployment rise and credit dry up.

Last month the government announced a 50-billion-euro (65-billion- dollar) fiscal stimulus package to help Europe's biggest economy weather the economic downturn. (dpa)