Local telcos were given the final approval on Wednesday by the country's regulator, Infocomm Media Development Authority (IMDA), to start building the two nationwide networks. They were provisionally selected in April and had to complete the regulatory process.
5G refers to the fifth generation of high-speed mobile internet that aims to provide faster data speeds and more bandwidth to carry growing levels of web traffic.
Singapore Telecommunications said it is in talks with Sweden's Ericsson to be the main vendor for its 5G and localized networks. Separately, a joint venture between Starhub and M1, called the Joint-Venture Consortium, said it selected Finland's Nokia as the preferred technology partner to build its 5G network.
Singtel and the joint venture between Starhub and M1 will each build a standalone 5G network. These are infrastructure designed using 5G-specific technologies, providing wide-area coverage using the most efficient spectrum available. They are also very expensive to build.
All four telcos in Singapore are also going to offer localized 5G services.
Last October, IMDA clearly spelled out Singapore's requirements in terms of performance, security, and resilience that local telcos must ensure their 5G networks have, according to the country's minister for communications and information, S Iswaran.
He told CNBC's "Squawk Box Asia" on Thursday that Singapore did not prevent Huawei from participating in the city-state's 5G infrastructure. He pointed out that few of the telcos were looking at working with the Chinese firm as well as its Shenzhen-headquartered rival, ZTE, on some parts of the networks.
Starhub said Nokia is the preferred technology supplier for its localized network. It added that it is exploring other network elements with various vendors including Huawei and ZTE. M1 said it will look to work with multiple vendors, including Huawei, to deploy localized networks.
IMDA said that TPG Telecom, which lost out on the bid to build one of the standalone networks, will be allocated spectrum to roll out localized 5G networks. Huawei is a supplier for TPG.
"If you look at it purely by its outcome, it's very clear - a) we did not specifically exclude any vendor, b) the process has been a rigorous and competitive one and c) the outcome is an ecosystem where there are diverse players," Iswaran said. "I would add, as we look ahead, our 5G ecosystem will continue to evolve and there will be more opportunities for various technology players to participate."
Huawei is one of the major names in the race to build 5G infrastructure. But, the United States has accused the company of including security vulnerabilities in its hardware that could be used for espionage by Beijing. Washington has urged its allies to exclude the tech firm from their 5G networks. Huawei has denied allegations that it colludes with Chinese intelligence.
Iswaran explained that the resilience and security of Singapore's 5G infrastructure was a major consideration in the city-state's selection process. The technology would enable more data, greater device density, faster throughput rates and lower latency.
"There has been no compromise on the standards, we have adopted not just from best practices around the world, but also looking at our own circumstances and our various agencies have specified it very clearly," he said, adding that IMDA is satisfied that the winning telcos have met all the necessary requirements.
IMDA said in April that telcos will have to roll out 5G standalone networks from January 2021. They would also be required to provide 50% islandwide coverage by the end of 2022 and full coverage by the end of 2025.
Iswaran on Thursday said he expected the telcos to move in response to the market demand and once the use cases for 5G become apparent, they will move a lot faster.