The Land Transport Authority (LTA) yesterday extended the deadline of its latest bus tender by three weeks, apparently to give bidders more time to rework proposals.

The tender to run 26 bus routes, called the Seletar package, will close on Oct 27, instead of Oct 6. It opened in June.

Industry sources said this is likely due to the recent spate of resignations of bus captains from new operator Go-Ahead Singapore, over the unpopular practice of driving multiple routes, called interlining.

The British-based Go-Ahead won the tender for the Loyang package in November last year for $497.7 million, the lowest bid among the eight short-listed bidders.

The LTA is believed to be giving bidders for the Seletar tender more time to tweak their proposals to scale back the use of interlining.

Interlining allows operators to optimise resources and keep costs down, and is practised in cities such as Perth and Sydney.

An industry source, who declined to be named, said: "Go- Ahead Singapore had possibly convinced LTA that interlining works. But its experience shows that it's not welcomed by bus captains here.

"Bidders are now scrambling to adjust the bus scheduling in their proposals."

About two weeks after starting operations on Sept 4, Go-Ahead entered into "short-term sub-contracting arrangements" with SBS Transit and SMRT.

The two firms loaned Go-Ahead 40 drivers in all.

The firm, which has more than 660 bus drivers, had about 20 driver resignations recently.

Another source said: "This red- flagged to the LTA the potential issues with interlining. LTA now expects bidders to learn from the Go-Ahead experience, and it wants to see the necessary precautions around any interlining."

At least nine companies and consortiums have expressed interest in the Seletar tender, including SBS Transit, SMRT, Tower Transit and Go-Ahead.

They are up against Australia's Busways, Singapore's Woodlands Transport, Britain's National Express with two consortiums, Kumho Buslines-Tian San Shipping, and Travel GSH-Jiaoyun Group.

Travel GSH and Tian San are local firms; Kumho is from South Korea and Jiaoyun from China.