* Countercyclical buffer rate rises to 1 pct from July 2018
* C.bank says increase due to rapid credit growth
* Seeking law to help it stay ahead of mortgage market
* Says banking sector highly resilient to potential shocks (Adds quotes, banks, more on law, details)
By Robert Muller and Jason Hovet
PRAGUE, June 13 (Reuters) - The Czech central bank on Tuesday said it was doubling the amount of money domestic banks must put aside as a precaution for hard times from July next year because of rapid credit growth.
The move comes as a bill allowing the central bank to make lenders cap loans, if needed, is at risk of failing in parliament, drawing sharp criticism from the bank's Governor Jiri Rusnok on Tuesday.
Czech lending growth is close to the fastest since 2009 as record low interest rates spur demand, especially in housing, where low supply and cheap mortgages have driven up prices on new apartments in Prague by a fifth in the past year.
Economists and real estate experts have yet to call it a bubble but, seeking to get ahead of problems, the central bank has taken steps such as giving banks recommendations to limit mortgage sizes - for which it now wants legal power to enforce.
The bank has also set a countercyclical "bad times" buffer rate on banks of 0.5 percent valid from this year which will double to 1.0 percent from July 2018. The bank said it stood ready to increase the rate or cut it, depending on developments.
"We are a country where property prices are probably rising the fastest in the whole European Union, so risk features are clearly present on the horizon," Rusnok told reporters. "That is why we are trying to react and approach this reasonably."
He added the bank would have decided to raise the buffer rate regardless of the state of the draft law in parliament.
Czech banks made it through the global financial crisis almost a decade ago relatively unscathed and remain highly capitalised but some have cut back dividends in reaction to higher capital requirements.
The biggest banks in the country are CSOB, owned by Belgium's KBC, Ceska Sporitelna, owned by Austria's Erste Group Bank, and Komercni Banka, owned by France's Societe Generale.
Prague-listed shares of Komercni Banka and Moneta Money Bank were little changed on Tuesday.
Lending strength has been helped by strong economic growth and the lowest unemployment in the European Union, boosting wages. But rising house prices, especially in Prague, are beginning to exclude some from the market.
The draft bill would allow the central bank to cap loans according to debt-to-income, debt-servicing-to-income and loan-to-value ratios. Opponents say it will shut young couples and families out of the market.
Since April, the bank has recommended banks provide mortgages that should not exceed 90 percent of property values.
In its annual financial stability report, the central bank said the banking sector remained resilient to potential shocks and would maintain solid capital adequacy even in a "very unlikely" adverse scenario projected by stress tests. (Additional reporting by Petra Vodstrcilova; Editing by Jeremy Gaunt)