By Marcin Goettig and Pawel Sobczak

WARSAW (Reuters) - Ukraine's economy is starting to disintegrate, creating a risk of hundreds of thousands of immigrants flowing into Poland, Polish Deputy Prime Minister Janusz Piechocinski said.

Piechocinski, leader of the centre-right junior coalition partner PSL, told Reuters he thought Ukrainian elites had made disappointing progress in building a Western-style democracy.

He defended comments by PSL presidential candidate Adam Jarubas who called for a softer stance toward Russia over Ukraine, signaling frictions in a government coalition that ranks as one of Kiev's most outspoken supporters in its battle with pro-Russian insurgents.

"These signals which are coming from Ukraine are very disturbing, because the economy there is beginning to disintegrate, economic ties are beginning to disintegrate," Piechocinski said in an interview.

“In a black scenario of developments in Ukraine, one cannot exclude an inflow of a few hundred thousand emigrants to Poland. Looking at what has happened during the last year, one has to take into account all scenarios and be ready.”

The strongly pro-Kiev line is firmly backed by the ruling Civic Platform (PO) party and the largest opposition party and seems unlikely to change. But the PSL comments could win support among voters concerned about the possible security implications for Poland of the Ukraine crisis.

COLLAPSING CURRENCY

The PSL is the third-biggest party in parliament, with 39 MPs in the 460-seat lower chamber. Polls, however, give PSL candidate Jarubas less than 5 percent of votes for May presidential elections.

Jarubas has said Poland had failed to gain political influence from its stance on Ukraine, but had sustained large economic losses due to sanctions.

Defence Minister Tomasz Siemoniak called these comments an "unnecessary excess".

Kiev and the West accuse Moscow of backing a pro-Russian rebellion in eastern Ukraine and the European Union has imposed sanctions on Russia. Russia, which denies involvement, has responded with counter-measures including embargoes on food imports that have had a particular impact on Poland.

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"Unfortunately, the elites have disappointed. One year ago it seemed that Ukraine was on course to become a stable, predictable democracy of our sphere of values," Piechocinski said.

Ukraine has come under increasing economic pressure from a collapsing currency and a threat to its gas supplies from the Kremlin, just as a long-awaited ceasefire took hold in the east at the end of February.

It is also grappling with serious problems of corruption.

(Reporting by Marcin Goettig and Pawel Sobczak; Writing by Marcin Goettig; editing by Ralph Boulton)