Residents of the sprawling city of 11 million often say they lack public green spaces, with greenery only available for the wealthy -- something Governor Chadchart Sittipunt has pledged to change.

Beguiled early European visitors once called Bangkok the Venice of Southeast Asia, but residents now contend with hazy traffic jams and a distinct lack of public space.

"You can see our city has many nice private properties but in terms of public investment, it is really bad," retiree Suvit Chandthanakit, 61, told AFP.

The Bangkok Metropolitan Authority operates around 40 parks, but intends to double that number by adding flora to small disused plots hemmed in by motorways or high-rise buildings.

Spokesperson Aekvarunyoo Amrapala told AFP the parks -- which contain walking tracks, sport courts and other exercise areas -- are an effort to provide green spaces.

"It's a big city so we try to make use of spaces to provide some nature," he said.

Under two thrumming highway overpasses, office worker Pattaree Klongkongmuang is taking a stroll around Somdet Saranrat Maneerom Public Park.

"I just come here to avoid traffic because I finish work at the office at rush hour," said the 36-year-old.

"I parked my car and walked around the park for an hour."