(Repeats story published late on Monday)
* Data reflects new foreign trade calculation
* Worse deficit may weaken CZK, or make it more volatile
By Jana Mlcochova
PRAGUE, March 14 (Reuters) - The Czech current account showed a 0.31 billion crown deficit in January on a large revision that cut the trade surplus and analysts said this could make the crown currency volatile or weaken it in the mid-term.
A potentially weaker currency, along with an expected pick-up in domestic demand, may eventually push the Czech central bank to raise interest rates, economists said.
The bank did not say what the January result would have been without the revision. Last week, it revised 2009 and 2010 current account data following a change in methodology by the statistics office in calculating the foreign trade balance.
The revision showed a steep rise in deficits in both years and translated into a deficit of 139.2 billion crowns ($25.2 billion), or 3.8 percent of gross domestic product, at the end of December, much larger than the originally reported 92.9 billion crowns, or 2.6 percent of GDP.
"The change of important macroeconomic variables ... is likely to have a negative impact on the crown over the medium term," said Miroslav Plojhar, an EMEA economist at JP Morgan.
"We do not think it will completely change the long-term convergence story of a strengthening crown. But it will show current crown strength may be a bit overdone." <EURCZK=><CZK=>
The statistics office began to release data on foreign trade in goods this month calculated according to methodology which excludes branding, or margins paid to companies that are not Czech and are merely registered in the country to pay value added tax (VAT).
It now looks at changes in ownership of goods between residents and non-residents. It is calculated on the basis of value-added, or sales, tax reports.
The office said it had excluded import and export values for branding that had artificially inflated the goods trade surplus and weakened the services balance. The change was intended to be neutral but in practice under the new calculation method the central bank found the true value attached to branding as a services import was greater than it had estimated.
Plojhar said many funds had made their investment decisions based on models which included key data from each country and did not look in depth into individual countries' macroeconomics.
"(The new data) makes the crown prone to higher volatility and sensitivity because it is showing that the external imbalance is larger than thought," said David Marek, a chief analysts at Patria Finance.
Plojhar added a potentially weaker crown combined with stronger domestic demand "may change the central bank's view on the appropriate level of interest rates. This would support our case of higher-than-priced-in interest rates over the medium term."
The crown shrugged off the data on Monday, trading at 24.33 per euro following the data release, marginally weaker from 24.32 ahead of the data release.
(Editing by Ruth Pitchford)