Tenders have been called for operators to run 56 bus routes across the Bulim and Sembawang-Yishun packages.
The Bulim package consists of 29 routes; the Sembawang-Yishun one has 27. As with all government bus contracts, the tenures are for five years.
This tender marks the second term for the Bulim bus package, which is up for renewal in 2021, while the Sembawang-Yishun one is the fifth tendered contract under the Government's bus contracting model (BCM).
There are a total of 14 route packages under the BCM.
The tenders will close at 4pm on March 30 and are expected to be awarded in the second half of the year.
This is the first time the Land Transport Authority (LTA) has concurrently called for tenders for two packages - a process it says it is exploring to achieve "economies of scale".
The LTA said it can award the two packages to the same operator or two different ones, depending on the bids.
"The bid which allows us to get the best value for money and (to) enhance the service levels of our bus industry will be awarded the tender," LTA added.
The current Bulim package comprising 26 routes was first awarded to British transport operator Tower Transit, which began operations out of Bulim Bus Depot in May 2016.
Over its five-year contract, Tower Transit is expected to receive about $556 million in fees.
SMRT Buses, meanwhile, has been operating the 25-route Sembawang-Yishun package since September 2016.
The tender listing on government procurement site GeBIZ states that bidders must submit offers for the Bulim package, the Sembawang-Yishun package and a combined Bulim/Sembawang-Yishun package.
The requirement to bid for a combined Bulim/Sembawang-Yishun package could mean LTA is looking to attract more foreign transport players here on a marginal cost base, said Singapore University of Social Sciences transport expert Park Byung Joon. But he was unsure if it would be an attractive business proposition for them.
Tower Transit Singapore managing director Winston Toh said the company "welcomes the opportunity" to bid for the packages and said it believes it has delivered "good service" for its customers.
Under the BCM, the LTA first sets out the bus services to be provided as well as service standards, and operators then bid to operate these services, receiving a fee in return.