* Q1 net 1.7 bln rgt vs 1.58 bln expected
* Q1 loans grew 14.3 pct year on year
* Rest of 2015 to remain challenging (Add CEO comment from statement, context)
KUALA LUMPUR, May 28 (Reuters) - Malayan Banking Bhd (Maybank), Malaysia's No.1 lender by assets, posted a better than expected 6.3 percent rise in quarterly profit on higher fee income and robust loans growth but gave a cautious outlook due to the launch of a new consumer tax.
Net profit for January-March was 1.7 billion ringgit ($466.65 million) compared with 1.6 billion ringgit a year ago, Maybank said in a stock exchange filing. This is higher than the average 1.58 billion estimate of two analysts, according to Thomson Reuters data.
Maybank, which is also Southeast Asia's fourth-biggest bank, faces a challenging environment in the region this year as economic growth slows and currencies depreciate. At home, the lender sees weakening private consumption growth in the coming quarters, due to the implementation of a goods and services tax (GST) in April and the persistence of high household leverage.
Smaller rival CIMB Group Holdings Bhd announced last week a 45.6 percent drop in first-quarter net profit, dragged by higher corporate loan provisions in Indonesia.
"The rest of the year is expected to remain challenging and we are closely monitoring regional developments, particularly the level of business activity post implementation of GST in Malaysia," group president and CEO Abdul Farid Alias said in a statement.
Maybank's first-quarter revenue rose 9.9 percent to 9.18 billion ringgit. Loans for the quarter expanded 14.3 percent year on year, led by its international markets which grew 19.4 percent, according to the statement.
Shares of Maybank ended the midday break 0.6 percent lower at 9.09 ringgit per share, prior to the earnings announcement. They have dropped 8.1 percent over the past year, underperforming the benchmark stock index, which declined 6.0 percent. Rival CIMB has dropped 23.2 percent over the same period.
For the full filing, please click: bit.ly/1FEvwrP ($1 = 3.6430 ringgit) (Reporting By Yantoultra Ngui; Editing by Muralikumar Anantharaman)