Workers from India and Indonesia are scrambling to change money as their currencies languish at multi-year lows.
Others are rushing to send funds home after the rupee and rupiah declined sharply over the past week.
Remittance shops and money changers in areas such as Serangoon Road said that they had been serving up to double the usual number of customers from both countries since Monday.
One Singdollar now buys 8,520 rupiah, up from 8,111 last week, and 50.3 rupees, up from about 48 a week ago.
The workers are paid in Singapore dollars and can now exchange their money for more of their own currencies.
Those interviewed yesterday said they wanted to cash in on the favourable exchange rates by sending as much money home as possible.
They go to the remittance companies with Singapore dollars, convert them into rupees or rupiah, and send them to their families.
Other workers said that they are exchanging their Singapore dollars for their countries' currencies, to use when they go home.
Some are so anxious to take advantage of the favourable exchange rate that they have been asking for time off work so they can send money home.
Indian construction worker P. Sundar, 41, remitted $200 yesterday at Western Union's Owen Road outlet. "The exchange rate may not be as good if I wait longer," he said.
Indonesian maid Purwati, who goes by one name, even asked her employer for two months' pay in advance. The 36-year-old then sent the $1,000 to her family in Java.
Her employer, 61-year-old housewife Serene Eng, said: "I do not mind giving my maid an advance salary. The exchange rate is so good, it will be a pity if she does not make use of it."
Ms Sahakrin Dinika, a customer service officer at Western Union in Owen Road, said about 300 Indian workers had been coming in every day since Monday, double the usual 150.
"At times we were worried that we would not be able to serve all customers by our closing time," she said. "But so far we have been able to do so."
Mr Humayun Kabeer, who owns a currency exchange shop at Paya Lebar's City Plaza, expects another surge in customers on Sunday when domestic workers get a day off.
"The rate is so good, I am sure many maids will want to exchange money," he said. "I told my staff they must be prepared to work overtime on Sunday."
Anxious investors are bailing out of shares, bonds and currencies in Asia on fears that the United States will relax its huge economic stimulus programme.
They fear that this will reduce the liquidity that has kept world markets buoyant and send American interest rates up - an outcome that might make investments there more attractive than those in Asian economies.
Weak emerging markets such as Indonesia and India have been worst hit.