* Plan to keep outgoing cabinet for as long as possible
* Aim is to reduce disruption while Poland holds EU presidency
* Some key ministers expected to keep posts in new govt
WARSAW, Oct 13 (Reuters) - Polish Prime Minister Donald Tusk, back in power for four more years after winning an election, confirmed on Thursday plans to govern again with the small Peasants' Party, renewing a coalition that has presided over strong economic growth.
But, in his first news conference since Sunday's election, Tusk said the swearing in of a new government would be delayed to minimise disruption to Poland's presidency of the European Union, which lasts until the end of the year.
Tusk's pro-business, centre-right Civic Platform (PO) won 207 seats in the new 460-member lower chamber, or Sejm. In coalition with the rural-based Peasants' Party, it would command a small but fairly safe five-seat majority in the chamber.
"I have held talks with (Peasants' Party leader) Waldemar Pawlak and he agrees with me (on renewing the coalition)," Tusk said.
The main opposition party, the right-wing, Eurosceptic Law and Justice party of Jaroslaw Kaczynski, won 157 seats.
Tusk said he would keep up to six current ministers in his new cabinet. They are expected to include Finance Minister Jacek Rostowski, Foreign Minister Radoslaw Sikorski and Defence Minister Tomasz Siemoniak.
A pragmatic liberal conservative from Poland's Baltic coast, Tusk, 54, said he wanted his outgoing cabinet to remain in place as long as possible to ensure administrative continuity for the country's six-month EU presidency which ends on Dec. 31.
Civic Platform, allied to German Chancellor Angela Merkel's Christian Democrats in the European Parliament, is keen to put Poland at the heart of EU diplomacy and a smooth, successful presidency of the 27-nation bloc is important for Tusk.
It is the first time Poland has held the EU's rotating chair. It hands over the baton to Denmark on Dec. 31.
Tusk won re-election on promises of continuity and a gradual approach to economic reforms, portraying himself as a "safe pair of hands" at a time of deepening crisis in the euro zone, Poland's main trade partner.
Poland was the only European Union member to avoid recession during the 2008-09 global economic crisis, but its debt and budget deficit rose sharply and investors now want Warsaw to put its public finances on a sounder footing.
Tusk has ruled out radical reforms, though ratings agencies say Poland could face a downgrade if it fails to take resolute action to reduce its budget deficit, expected to reach 5.6 percent of gross domestic product (GDP), and curb public debt.
On Thursday Tusk said he would propose the outgoing health minister Ewa Kopacz as new speaker of parliament. She would be the first woman to hold the post and would rank second in the state hierarchy after the president.
He ruled out any coalition deal with the third largest party in the new Sejm, Palikot's Movement, as "too risky". The ultra-liberal party of maverick former PO lawmaker Janusz Palikot backs gay rights, abortion and legalisation of marijuana.
Palikot, who also wants to eliminate privileges for Poland's powerful Roman Catholic Church, won 10 percent of the vote, ahead of the once-mighty post-communist Democratic Left Alliance and also more than Pawlak's Peasants' Party.
Head of state, President Bronislaw Komorowski -- a Tusk ally -- must convene a new parliament within 30 days of the election and name a prime minister after two more weeks. Tusk would then have two further weeks to win a parliamentary vote of confidence for his cabinet.
"I plan to call the first sitting of the new parliament at the very latest date possible, that is on November 8," Komorowski said on Thursday.
This timeframe means a confidence vote on the new government could be delayed until as late as Dec. 6. (Additional reporting by Dagmara Leszkowicz, writing by Gareth Jones and Gabriela Baczynska; Editing by Matthew Jones)