(Updates with details from letter to party)
AMSTERDAM, Oct 11 (Reuters) - Outgoing Dutch Finance Minister and Eurogroup head Jeroen Dijsselbloem will leave national politics when a new government takes office in approximately two weeks, he wrote in a letter on Wednesday.
Dijsselbloem's Labour party was heavily defeated in the March 15 election and will not be part of the new government, agreed this week after months of coalition talks.
"I am leaving Dutch politics. It is not easy," he wrote in a letter published by the party.
"I have reached the conclusion that is this position, this stage, I don't have the fire power."
Dijsselbloem did not say what he intends to do when he steps down on Oct. 25 but has already said he will complete his term as head of the Eurogroup of euro zone finance ministers which expires in mid-January. (Reporting by Toby Sterling and Anthony Deutsch; Editing by Catherine Evans)