* Non-performing loans rise to 8.3 percent from 7.8 percent
* Household mortgages NPL up to 7.3 percent from 6.5 percent
* Swiss franc's rally hits Hungarian FX mortgage holders
(Adds more detail, background)
BUDAPEST, Aug 9 (Reuters) - The rate of non-performing loans in Hungary rose in the first quarter, hit by an increase in non-performing foreign currency-denominated household mortgages, financial regulator PSZAF said on Monday.
The regulator said there could be a further acceleration in the increase in non-performing household foreign currency loans in the second quarter, due to the rally of the Swiss franc in June and July.
Swiss franc loans make up about 44 percent of Hungary's entire household debt stock -- and 55 percent of all mortgages, as a result of massive borrowing in the foreign currency prior to the 2008 global crisis.
The regulator said 97,000 household mortgages were more than 90 days late with repayments at end-March.
The non-performing loan rate within the total credit stock of the Hungarian financial sector rose to 8.3 percent at the end of March from 7.8 percent in December, while households' non-performing loan rate rose to 10.1 percent from 9.3 percent.
While at the end of December 6.5 percent of household mortgages - most of which are in Swiss francs -- were more than 90 days late with payment, this rate rose to 7.3 percent by the end of March 2010, the regulator said in a report.
It said the increase in non-performing loans, which showed a steadily slowing pace in previous quarters, picked up again early this year.
"This could, to a significant extent, be related to a strong appreciation of the Swiss franc versus the forint. A sign of this is that the rate of late paying household mortgages increased at a faster than average pace," PSZAF said.
"It is also noteworthy that a part of previously restructured loans fell into the late payment category again."
The Swiss franc's rally to a record high against the forint to levels around 219 drove up debt costs for a majority of Hungarian mortgage holders in July..
The forint traded at 202-203 versus the franc on Monday, but still much weaker than the levels at which most mortgages had been taken out
The centre-right government, which took office in May, has banned further foreign currency mortgage lending to households, but analysts have said the large outstanding stock of forex loans will remain a key vulnerability for Hungary for years to come.
Banks' non-performing household loan rate rose to 8.0 percent from 7.2 at the end of last year, the regulator said.
The banking sector, however, had showed an improvement in its profitability and capital position in the first quarter.
It said key risks for banks were a continued deterioration of assets and a weakness of the home and car markets. A further risk was a special tax on banks and a ban on foreign currency mortgages planned by the government, PSZAF said in its report which had been drafted before parliament approved the plans.
The government wants to raise 200 billion forints in taxes from the financial sector both this year and in 2011 in order to plug budget holes, in a move criticised by the banking sector and Hungary's lenders, the International Monetary Fund and the European Union. (Reporting by Krisztina Than; Editing by Dan Lalor and Simon Jessop)