* AgBank Q1 net profit up 4.3 pct on-year, below estimates
* Non-performing loan ratio 1.53 pct end-March vs 1.59 pct end-Dec (Adds milestone, bullet points)
SINGAPORE/BEIJING, April 26 (Reuters) - Agricultural Bank of China Ltd (AgBank) , the country's third-largest lender by assets, reported on Friday a 4.3 percent on-year rise in net profit for the first three months, its slowest first-quarter growth since 2017.
AgBank, which is the first of China's largest state lenders to report first-quarter earnings, said net profit for the first three months of the year totalled 61.25 billion yuan ($9.09 billion), versus 58.74 billion yuan a year earlier.
That was below the 5.5 percent average of three analyst estimates compiled by Reuters.
The result came as a slowing economy and tougher regulations to curb financial risks continued to weigh on profitability and asset quality at the country's larger banks.
AgBank's non-performing loan (NPL) ratio fell to 1.53 percent by March-end from 1.59 percent at the end of 2018. But the outstanding amount of NPLs at the bank increased by 2.7 billion yuan over the three-month period to 192.7 billion yuan.
The bank did not disclose its net interest margin for the quarter.
AgBank last month reported a 5.4 percent fall in October-December net profit, its first quarterly decline since 2015.
AgBank's mainland shares fell 0.53 percent on Friday ahead of the results announcement. They have gained about 6 percent in 2019, compared with an around 31 percent rise of the blue-chip CSI300 index, giving the bank a market value of 1.29 trillion yuan, Refinitiv data showed.
($1 = 6.7351 Chinese yuan renminbi) (Reporting by Shu Zhang in SINGAPORE and Cheng Leng in BEIJING; Editing by Christopher Cushing and Rashmi Aich)