* Czechs plan three bond auctions in May
* Adds third April auction
* Markets brace for new supply, await midday auction
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PRAGUE, April 1 (Reuters) - The Czech Republic will offer 21 billion crowns ($1.02 billion) worth of state bonds in May and plans an extra April auction to take advantage of a rise in demand that has slowly unthawed central Europe's debt markets.
The Finance Ministry will offer 6 billion crowns of its 3.55 percent 2012 bond, along with 7 billion crowns of a 3-year floating rate bond that debuts in April. It will also introduce a new 15-year fixed-rate bond at a May auction, it said.
It will offer an additional 7 billion worth of bonds in April, on top of 15 billion crowns already planned, through an auction of its 10-year bond due 2019.
The ministry added it would auction short-term domestic treasury bills worth 21 billion crowns in May.
The Czechs have picked up their borrowing pace in the last month after a cautious approach since central Europe's markets were hammered last autumn by the widening global financial crisis.
The ministry put on hold a planned eurobond issue in February due to widening credit default swap prices in the region, but last month it sold 35.4 billion of bonds in March at three domestic auctions, almost a third more than planned.
However, it has come at a price, because yield have steadily ticked up and markets are bracing for more supply that will likely hurt secondary markets.
"I'm afraid on the long-end there will not be such demand," said a local fund manager. "The new calendar is quite a lot, so I would expect spreads to widen."
The ministry planned to auction its 4.7 percent coupon bond due 2022 at midday on Wednesday.
The 15-year bond <CZ15YT=RR> was quoted 86.50/88.50, yielding 6.207/5.965, by 0908 GMT. It traded with an asset swap spread of 205.4 basis points, up from 107 bps to start the year.
"(The new debt supply) should be quite negative for today's auction," said Komercni Banka dealer Dalimil Vyskovsky.
Analysts also warn the new debt supply could grow this year, especially after a no-confidence vote last week sank the minority government. The main political parties are now negotiating over pushing through new economic measures through parliament that will likely push up the deficit.
The government has already adopted a series of stimulus measures, and expects budget deficit of around 4 percent of GDP.
The opposition introduced on Tuesday a package of 15 measures it says will cost 44 billion crowns ($2.13 billion) annually over the next three years, or around 1.1 percent of gross domestic product.
For a TABLE with auction details, click on [
] (Reporting by Jason Hovet; Editing by Victoria Main)