A caretaker contractor will be appointed to ensure safety on a stalled section of the Downtown Line Stage 2 after the main contractor went bust.

A delay in the project and additional costs to complete the project are expected but the extent will be known only after the Land Transport Authority (LTA) makes an assessment in a few weeks, said Transport Minister Lui Tuck Yew in Parliament on Tuesday.

Austrian builder Alpine Bau was working on the line's King Albert Park, Sixth Avenue and Tan Kah Kee stations until it filed for insolvency last month.

Mr Lui assured MPs Sylvia Lim (Aljunied GRC) and Chris De Souza (Holland-Bukit Timah GRC) that the LTA's immediate priority was to ensure the safety and security of the worksites and equipment.

This included securing partially-completed structures, calling in specialists to maintain tunnel boring machines and recharge wells, and ensuring Alpine's workers were properly looked after.