In HCMC, the average asking rent for grade A office space has edged up to $52.2 per square meter per month from below $50 in the fourth quarter of last year, according to a report by real estate firm Colliers International Vietnam. 

In Hanoi, rents were up to $35.9 from below $35.

"Rents are expected to continue to rise thanks to strong demand for office space and Hanoi’s improving economy," the report said.

Both cities have high occupancy rates. In HCMC the first quarter rate was 95 percent, while in Hanoi it was 96 percent.

Despite their high rents, grade A offices are still preferred by large international companies in HCMC due to their ease of access, premium image and facilities.

In Hanoi, the improving infrastructure would continue to attract big-name office tenants to the market such as banking, finance and insurance companies.

The west of Hanoi is the up-and-coming office destination in the city thanks to the availability of land, well-established infrastructure and large supply of residential projects.

The low supply situation is set to improve with five new high-quality office buildings set to open this year in HCMC with 150,000 square meters of leasable area. Hanoi is also likely to add 150,000 square meters this year, Colliers said.

"Both cities are seeing the flexible workspace and coworking space market grow to cater to high demand from startups and small and medium enterprises."

In the first quarter the average occupancy rate in this segment was 85 percent in HCMC, and this emergent market is promising to expand massively in the upcoming quarters, it added.