I refer to your article LTA ownself check ownself: http://www.allsingaporestuff.com/article/lta-outsourced-project-company-...
They did not just anyhow give out tender. They can do so legally.
In gebiz there is 2 tab, i.e. RFI and ITQ.
RFI - refer for information is a way government agency use to source for products and services. And may or may not eventually be a real tender.
ITQ - invitation to quote is a direct open tender.
The "legal" method is to hide their tender under RFI. And no serious businessmen would look at RFI as it seldom brings real business. Government agencies only use it to get free information. Hence very few businesses would do submission under RFI, instead most would wait for the actual tender to come out in ITQ.
However under RFI, the agencies can call for a CLOSED TENDER open only to the privileged few who submitted under RFI.
All done LEGALLY! This is the loop hole!
That's why don't anyhow say they didn't tender out the job. They did, just that they do not need to let we, the people, know only.