The labour shortage has seen builders offer lavish incentives ranging from cash to vehicles to keep workers from heading overseas, and in some cases, illegally employ foreign tradesmen to man projects.
Sri Lanka was left with a massive reconstruction task at the end of the civil war in 2009, with large parts of the north left in ruins by decades of fighting.
Annual investment in new homes, roads and ports -- which has hovered at around 600 billion rupees (USD 4 billion) in recent years -- is expected to almost triple to USD 11.6 billion in 2017.
"We can't get that many overnight and we will have to import. We are now facing a serious labour crisis," he said.
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Private contractors are going to extreme lengths to stop the flow of tradesmen heading to the Gulf for construction jobs, offering bonuses like motorcycles and cars to labourers who choose to work on projects back home.
The government has taken a different approach and sought to put curbs on migration by raising the minimum wage requirements for workers heading overseas.
"We want to discourage those who go abroad for low pay. Some of these workers can get more money if they stay back in Sri Lanka," Finance Minister Ravi Karunanayake told AFP.
But it is a risky strategy. Roughly one in ten Sri Lankans work abroad and their remittances are the number-one foreign exchange earner for the island of 21 million.
The pool of money flowing home is growing, with Sri Lankans sending USD 7.24 billion last year compared with USD 6.98 billion in 2015.
"There is a social perception about construction industry labour, and that is why young people prefer public sector jobs even if they pay much less," Wijeratne said.
"It is about social acceptance."
The dearth has spurred some desperate contractors to look offshore themselves -- not for work but workers. The government estimates roughly 200,000 foreigners are employed illegally in the construction sector.
"I am proposing that the government come up with a policy on foreign workers to regularise this sector."
One company, which declined to be identified, said it was employing foreign workers illegally but noted that many others were doing the same.