Jin said companies were concerned about how much they could earn from the partnerships as these projects are usually long and sometimes risky.
Sun and Jin said Wednesday's measures offer beefed-up financial support for PPP operators and reassurance that these projects can be profitable.
Another reason for the current lack of PPPs is that companies are skeptical whether powerful governments will behave in accordance with market rules.
Jin advised that PPP projects need strict contracts and that every detail involved in the cooperation should be prescribed beforehand.
"A sound PPP is like a marriage," he said. "Both sides are supposed to work to nurture the relationship over its lifetime, rather than quarrel over how many presents each can get from the wedding."