They outlined their concerns at a dialogue session held on Tuesday night at the Institution of Engineers Singapore (IES), as a government-led body - the SME Workgroup - continues to gather feedback on the ground.
Architectural bosses said they faced difficulties in bidding for government projects.
For example, small and newly set-up firms do not meet the minimum criteria for entering a tender process as they do not have the requisite track record or qualified persons.
Singapore Institute of Architects council member Lim Choon Keang said: "I think you can have some concessions for a start-up company instead of purely looking at a company's track record. I just started three months ago, how am I going to get even a $1.5 million project track record?"
Firms wishing to provide consultancy services for public sector building and construction projects must be listed with the Public Sector Panels of Consultants (PSPC).
To be on the list, they must satisfy requirements including having a certain number of registered professionals or having completed projects of a minimum value, depending on the size of the government project.
At the same session, engineer Fang Koh Look outlined difficulties he faced in attempting to work with the Government.
Now the boss of a private safety training company, he said he wanted to be a course provider with the Building and Construction Authority (BCA).
But he said he was rejected by the agency as his firm was deemed a service provider, not a contractor, and ineligible to provide industry courses.
"I hope in the near future, BCA can consider liberalising, so that service providers who are not classified as contractors can do BCA training," he said.
BCA is "conducting our regular review on our selection criteria" so any appointed training provider can meet industry needs. On the issue of the PSPC, administered by BCA, the spokesman said the scheme allows firms to progressively upgrade their capabilities. There is also no track record requirement for firms wishing to tender for public sector projects of up to $4 million.
The dialogue session was led by Nee Soon GRC MP Lee Bee Wah, a past president of IES who runs her own engineering firm. Dr Lee said SME bosses raised manpower issues and rental costs among other issues.
"There is a lot of frustration, so I think it's good to give them this platform to voice out and it's also good for the government agencies' representatives to hear from them," she said.
High rentals and manpower issues were also key concerns for HDB shop owners at a separate session organised by SME Workgroup member, West Coast GRC MP Foo Mee Har.
She held a walkabout session in her Teban Gardens ward on Wednesday and said many shop owners were hesitant about flexible or part-time workarrangements due to bad experiences.