Phnom Penh’s old colonial Post Office sits in a sleepy corner of the city just away from the riverside. Its bell, used to mark curfew under the Khmer Rouge, no longer tolls.

In an urban design competition that concluded this week, architecture students from five university programs offered their takes on how to reinvigorate the historic district.

“It is a beautiful place, but now it looks too quiet. So we’ve designed it to be alive,” says Horn Sok, a student at Pannasastra University. His team’s model, which took first place, seeks to bring people back into the square.

In miniature, they have closed the carpark out front to traffic and reimagined it as a courtyard with seats, two movie screens and room for food stalls. Its centrepiece – termed the “Flying Envelope” – is a multipurpose event space with a roof shaped like a paper airplane.

The replica is a creative take on a task often left unaddressed in Phnom Penh: re-designing the old to fit the new.

Urban design for public consumption isn’t the priority in the capital, says Pen Sereypagna, an architect who co-organised the contest. “The thing is, in Cambodia, in this industry . . . everything is just focused on private buildings or apartment buildings. There is a lot of development in Phnom Penh,” he says. “But we don’t have enough public space.”

Architecture graduates have little problem finding jobs, but there are few who work as city planners. The Post Office square competition gave them the opportunity. The judges came from a few sectors, including the municipal government. “We see this competition as a way to bring people together and make a dialogue,” Sereypagna says.

One student winner, Hun Sokagna, who received her degree from the Royal University of Fine Arts in August, wants to pursue a career in heritage conservation. Design, she has learned, is about carefully considered intervention.

“Phnom Penh is developing in the wrong way. Buildings are not designed by architects, but engineers,” she says. “I want to develop Cambodia in the right way.”

An exhibition of the winning designs is on at the Community Art Gallery at the Asia Foundation, #59 Street 242.