An investigation into the delay of trains on the North South line on April 29 will be carried out by the Land Transport Authority (LTA).

The authority's vehicle and transit licensing group director Yeo Teck Guan said in a statement on Tuesday: "LTA will carry out an investigation into yesterday's delay, and this would include looking into the cause of the rail and train faults, as well as how SMRT managed the incident and information flow to commuters."

Mr Yeo added that LTA was aware of public feedback that SMRT needed to further improve on incident management, especially in providing more accurate and timely information in trains and stations across the train network so that commuters can make alternative travel arrangements.

On Monday, trains were delayed during the evening rush hour after a crack was found on the northbound track between Somerset and Orchard stations. SMRT said in a statement that it has since replaced the affected rail, and trains have been operating at normal speed from Tuesday morning, although the reason for the rail crack is still being investigated.