SINGAPORE - Repair works on the trails in Bukit Timah Nature Reserve will be done "in a sensitive manner", National Development Minister Khaw Boon Wan said in a blog post on Monday.

While boardwalks will need to be installed in some areas to prevent further erosion of the trails, these will be raised above the ground.

The wooden planks used to construct them will be also be "hand carried, piece by piece, into the narrow paths of the reserves," he added.

As previously announced, the reserve will be closed from September 15 as the National Parks Board carries out restoration work on its slopes and trails.

Mr Khaw noted that the reserve, visited by 400,000 people each year, has "undergone natural wear and tear". Some slopes have suffered landslides and trails have been eroded, exposing tree roots and affecting the stability of the trees.

"We are sorry for the temporary inconvenience but will minimise it through phasing the works," said Mr Khaw. Work will begin on the most commonly used parts of the reserve, and NParks will strive to re-open the grounds to visitors as soon as possible.

NParks will start with stabilising the slope along the main tarmac road next to the visitor centre. These works are expected to be completed within six months.

After March 2015, the main tarmac road will be reopened on weekends, so that visitors can go up to the summit. However, NParks will close this road on weekdays for use by vehicles carrying construction equipment.

The mountain biking trail that runs around the periphery of the reserve will not be affected, and will remain open throughout the restoration process.