An accident that led to the death of a construction worker from brain injuries was the result of a series of "uncanny coincidences", a district court said on Friday as it took a construction firm to task for the accident.

The accident, which saw the man being hit in the head by a steel bar falling eight stories, took place at a HDB worksite in Yishun some 20 months ago in 2012.

On Friday, Wee Hur Construction - the occupier of the worksite at the time of the incident - was fined $40,000 after pleading guilty to failing to extend overhead shelter coverage to protect the worker, Mr Ammaiappan Vijayendran. The Indian national was performing drainage installation works on the ground floor of a block of flats under construction, for a sub-contractor of Wee Hur's.

This left him exposed under a 2.96m stretch unprotected from falling objects. A falling bar, which was being used as a tool by workers on the eighth floor of the block, fell through the gap and onto Mr Ammaiappan's head - fracturing his skull and leading to his death in hospital two hours later, from brain injuries. Another worker was also injured after the bar bounced onto him.

In mitigation, Wee Hur's lawyer Yusfianto Yatiman urged the court to impose less than $40,000 in fines, saying the firm had taken "significant and pro-active" steps to prevent the incident.

These included ordering that no work be carried out on the ground floor until overhead shelter coverage was complete.

He also pointed to the "larger" role another sub-contractor and its employee had played in the tragedy.

As occupier of the worksite at the time, Wee Hur could have been fined up to $500,000 for failing to take measures to ensure the safety of people on the premises.