The Sri Lanka parliament has approved a special court to expedite trials of bribery and corruption cases amid public outcry against delays in punishing members of the island nation's former strongman's government.

On Wednesday, 119 lawmakers voted to pass the bill while 52 voted against establishing a permanent three-judge high court consisting of three judges.

Sri Lanka's government, led by president Maithripala Sirisena, won election in 2015 after promising to investigate alleged large-scale irregularities under predecessor president Mahinda Rajapaksa.

Since Rajapaksa lost power, two of his sons have been arrested and released on bail over money laundering allegations while his brother Basil Rajapaksa, who was economic development minister, has been arrested on suspicion of misusing public funds and released on bail.