By Johan Sennero and Simon Johnson
STOCKHOLM (Reuters) - The leader of Sweden's Moderate party said on Friday she would step down, leaving the main center-right opposition Alliance bloc without a clear candidate for prime minister just a year ahead of a general election.
Party criticism of Anna Kinberg Batra has been mounting in recent months as the Moderates have plunged in polls.
This is partly due to her attempt to find an accommodation with the anti-immigration Sweden Democrats who have otherwise been shunned by the mainstream political parties.
"If you are going to deal with difficult questions, that means you are going to have to take your knocks, especially if you are the first to do it," Kinberg Batra told reporters.
"The task has always been to put into practice as much Moderate policy as possible, and that means basing what you do on how things are in society and in parliament."
Sweden's usually stable bloc politics has been thrown into turmoil in recent years with the rise of the Sweden Democrats. Neither the center-left nor center-right is able to form a majority government without them.
Boosted by growing concerns over immigration, the Sweden Democrats are now the second largest party in the polls with much of their support coming from formerly Moderate party voters.
To counter that, Kinberg Batra shifted her party to the right, holding out an olive branch to the Sweden Democrats earlier this year, though she stopped short of offering them a place in a future government.
That has alienated liberal Moderates.
In a opinion poll by research institute Novus, published earlier this month, the Moderates were supported by 15.2 percent of voters, down from 23.3 percent in last general election in 2014. The Sweden Democrats regularly poll around 20 percent.
The question of how to deal with the Sweden Democrats has also split the four-party Alliance bloc which governed between 2006 and 2014.
The Centre and Liberal parties -- also in the Alliance with the Moderates -- have said they will not do any deals with the Sweden Democrats.
But without some kind of arrangement, it is hard to see either bloc forming a stable government. The current government is a minority coalition of Social Democrats and Greens.
The economy is surging and public finances are strong, but there is still pressing need for reform.
The housing market is overheated, there are shortages of doctors, nurses and teachers, while productivity growth has also been slipping, leading to calls for the government to use its surpluses to invest in infrastructure and other growth-boosting measures.
The next election will be held on September 9, 2018.
(Reporting by Johan Sennero and Simon Johnson; writing by Simon Johnson; editing by Niklas Pollard/Jermey Gaunt)