Home loan arrears of 90 days or more past due rose significantly in the December 2010 quarter and may increase further if the property market becomes stagnant, said Fitch, in its report on Australian mortgage arrears for the quarter.Arrears over 90 days rose to 0.54 per cent in Q4, compared with 0.48 per cent in Q3. Much of this was reflected in the 30-plus day delinquencies, which rose to 1.37 per cent, from 1.30 per cent. According to the ratings agency, the rise was unexpected because no particular event had been expected to affect mortgage performance in Q4.Separate data from Standard & Poor's also showed a rise in 90-plus day arrears, to 0.56 per cent in December, from 0.53 per cent in November. Fitch said the rise in 90-plus day delinquencies coincided with an increase in claims on lenders' mortgage insurance, which rose 32 per cent over the previous quarter to A$4.1 million. While a rise in claims indicates more properties are being sold, if the housing market turns stagnant such sales could decrease and thus push up 90-plus day arrears.Fitch, however, does not expect 90-plus day arrears to peak to the levels seen in 2008, and, in the absence of any adverse developments influencing the Australian economy or housing market, it expects arrears to return to historical levels.Delinquencies over 90 days also rose in the low-doc segment, increasing to 3.03 per cent from 2.79 per cent, to touch the highest level since July 2009. S&P data showed such delinquencies rising to 2.27 per cent in December, from 2.13 per cent in November and 1.99 per cent in October.An analysis of individual delinquencies showed that Bendigo and Adelaide Bank's Series 2005-2(S) Torrens Trust had 30-plus day arrears at 9.85 per cent in December. This figure rose further, to 10.7 per cent, in January. The higher delinquencies are because of a low-doc exposure of 97.9 per cent.  Fitch recently affirmed all rated notes, but said it will continue to monitor their performance.