Singapore's high-speed fibre broadband network builder has been fined $500,000 for failing to deliver orders to home and business users on time.

It is the fifth fine in four years for NetLink Trust, formerly OpenNet. Last year, it racked up a $450,000 penalty for similar reasons.

The Infocomm Media Development Authority (IMDA) imposed the latest fine after taking into consideration the company's previous failures to meet required standards, as well as the improvements it has made to raise performance across the board.

The fine includes $200,000 for causing delays to home users between January last year and June this year.

NetLink Trust fulfilled 87 per cent to 93 per cent of home users' orders within three business days, below the 98 per cent standard required by the IMDA.

The firm also has a duty to connect all residential orders within seven working days, but it did so only for less than 94 per cent of them.

The remaining $300,000 of the fine is for failing to meet the mark for business orders from January to December last year.

The firm needed to connect 80 per cent of new business sign-ups within four weeks of the order date. But it failed to meet this minimum monthly standard in 11 out of 12 months last year.

In addition, all business orders had to be completed within eight weeks, but the firm did not meet the mark.

The IMDA said in a statement yesterday that it will continue to monitor NetLink Trust's performance closely and expects the firm to improve its processes.

NetLink Trust said it accepts the fines. Its chief executive Tong Yew Heng said in a statement yesterday that the company is "fully committed" to improving its operations and performance.

"Addressing the expectations of the IMDA and our partners continues to be a priority for us," he said.

"We are investing about $150 million to install more fibre across the country and to upgrade the operational and business IT systems in order to deliver a robust fibre broadband network."