Malaysian banks' statutory reserve requirement (SRR) will be reduced to 3.00% from 3.50%, effective Nov. 16, the central bank said on Friday, the first cut in three years and made days after it left its key policy interest rate unchanged.

Economists said the move suggested that Southeast Asia's third-biggest economy was slowing down in the second half. It also sets the stage for an interest rate cut in Bank Negara Malaysia's (BNM) next policy review in late January, they added.

"The decision to reduce the SRR is undertaken to maintain sufficient liquidity in the domestic financial system," the central bank said in a statement.

"This will continue to support the efficient functioning of the domestic financial markets and facilitate effective liquidity management by the banking institutions."

BNM, however, said the SRR was not a signal on the stance of monetary policy.

The central bank on Tuesday maintained its key overnight policy rate at 3.00% - as expected - betting that private sector spending would offset pressure in the economy from weaker exports.

Malaysia's exports in September recorded their biggest decline in nearly three years.

Economists said the cut in SRR - the minimum amount of reserves that must be held by a commercial bank - should bring down the interbank lending rate and boost loan growth.

They said it was too early to say how much money the move would free up, but the last time the BNM cut the SRR in January 2016 from 4%, economists estimated it added 6 billion ringgit ($1.45 billion) to the system.

"It's a major move, it was totally unexpected given what they signaled just this week in the policy statement which was pretty much quite balanced in its tone of risk," ING Asia economist Prakash Sakpal said.