The city warned that some residents stood to lose land.

Bangkok Metropolitan Administration public works department director Banyat Ouiyamwong said new roads were desperately needed as the capital's population swelled.

The new roads would connect existing thoroughfares to reduce traffic jams, he said.

And, while the whole project was likely to take 10 years, the city would commence with 14 roads critical to ending the gridlock.

They included Soi Yasoob 1, Ramkhamhaeng Soi 40 following the banks of Rangsit canal, Wat Kuborn-Nawamin and Wat Kuborn-Ram Indra.

Banyat explained these works had been in the pipeline for four years but budget restraints had prevented work starting.

"We need cooperation from city people in land expropriation. We have to make people understand they need to sacrifice their land for the sake of the public," he said.

"We always face a problem with people not wanting to give up their land but they must understand every inch of this country is Royal property.

"Also, they must understand it is needed for roads to reduce traffic problems and for the benefit of the public."

Landowners could check at district offices to see if their properties were on a list of plots to be expropriated.

Complaints about unfair compensation could be taken to the Administrative Court, he said.