Singapore's fleet of around 60 F-16 jets are at the tail end of their service and Ng Eng Hen told reporters it needs to make a decision to replace them soon because training pilots and building facilities for new models can take up to 10 years.
With Southeast Asia's largest defense budget, the wealthy city-state is a key prize for global arms companies as it looks to invest in new technology and upgrade its equipment.
"Whether it's Typhoons, whether it's F-35s, whether it's Sukhois, even now Chinese-made stealth fighters. I mean these are the usual suspects that you have to look at," Ng said, Reuters reported.
He was referring to the Eurofighter Typhoon that is built by Britain's BAE systems and F-35s from US-based Lockheed Martin. Sukhoi is a Russian manufacturer.
A modern fighter jet costs roughly about $20-$100 million depending on the manufacturer.
Singapore should make a decision in the next few months "to make sure that we can replace our F-16s in time," Ng added.
Singapore's F-16s first entered service in 1998. The country has typically used US-made aircraft in the past, making the F35s - a variant of which appeared at the city-state's airshow back in February - a likely successor.
The head of Lockheed's international business said in February that Singapore was "seriously evaluating" a future purchase of F-35 jets - one of the world's most advanced fighters which start at around $80 million each.
He said initial talks with Singapore were centered on the F-35B short take-off and landing variant, which he described as "a nice fit for a smaller land-constrained environment".
Media reports show that Singapore had intended to buy four F-35s by around 2022, with the option to purchase another eight, but held off taking a decision on this in 2016.
Other F-35 customers in Asia include Australia, Japan and South Korea.
Britain's BAE has offered Singapore's neighbor Malaysia a UK government-backed financing deal to replace the country's combat jets with their Eurofighter Typhoon.