Buy-to-let lenders approved mortgages worth £3.5 billion between April and July in the sector's busiest quarter since the 2008 financial crisis.
There were 32,000 loans in the quarter, although the Council of Mortgage Lenders (CML) said its figures still showed the market is running at around one third of the level seen at the peak of lending in 2007.
Demand from buy-to-let investors has picked up in recent months as tight mortgage availability has caused the rental market to strengthen.
However, the CML pointed out that remortgaging accounted for 65% of the overall increase in buy-to-let lending in the quarter.
At the end of the second quarter, there were 1.34 million buy-to-let mortgages worth £154.5 billion, up from 1.26 million and £148.8 billion at the end of the same period in 2010.
The CML added that for the first time since 2008 the arrears rates for buy-to-let mortgages were lower than in the owner-occupied sector. At 28,100 or 2.09% of the total, loans over three months in arrears in the buy-to-let sector were 0.05% lower than in mainstream lending during the quarter.
However, repossessions in buy-to-let increased by 9% from 1,700 in the first quarter to 1,900 in the second.
CML director-general Paul Smee said yesterday's CML figures showing a 24% increase in first-time buyer loans during May indicated that newcomers to the market were not being displaced by buy-to-let landlords.
He added of today's figures: "This is encouraging news for those who want to rent, as long as it is realised that much of the current increase is for remortgage rather than house purchase."Reuse content