Singapore sovereign wealth fund Temasek will remain a long-term investor despite its early exit from Bank of America and the fund made $56 billion (US$38.5 billion) in the six years since March 2003, Finance Minister Tharman Shanmugaratnam said on Thursday.

"The facts are Temasek has produced strong returns over time," Tharman told Singapore's parliament.

"It is not realistic to outperform in every cycle."

The government has come under fire from Singaporeans and lawmakers over losses at state investment firm Temasek, in particular its ill-timed exit from Bank of America which resulted in a loss of over $3 billion.