Bangkok taxi drivers will on Monday swarm the Department of Land Transport (DLT) and the Bhumjaithai Party's headquarters, to protest against legalising ride-hailing services.
The rally comes amid reports that the DLT is pushing forward with plans to make services such as Grab, which involves private cars and motorcycles, legal.
Saksayam Chidchob, secretary-general of the Bhumjaithai, is tipped to become the transport minister and legalising the online ride-hailing service was one of the party's election pledges.
Withoon Naewpanich, head of the network of taxi cooperatives in Bangkok, said a group of about 60 taxi drivers will on Monday hand their demands to the department and the Bhumjaithai Party.
"Drivers want the department to come up with tangible measures to ease any impact of the policy, and make serious efforts to crack down on illegal taxi services," Mr Withoon told the media.
The group will also ask the new government to raise fares.
"Drivers are already struggling because taxi fares have not been raised for more than five years," he said.
He lamented the Bhumjaithai policy to legalise Grab, saying it would have an adverse impact on more than 80,000 taxi drivers in the capital.
He said drivers' incomes have reduced by 20% as a result of competition from Grab, adding there are currently 80,000 taxis as opposed to 20,000 GrabCar service drivers.
He added they also wanted the DLT to review its "Taxi OK" mobile application, which many said does not work.
Grab Thailand, the local operating unit of the Singapore-based start-up, has high hopes a new government will finally legalise the ride-hailing business after years of operating in the country.
The emergence of ride-sharing apps in Thailand has resulted in vehement opposition from public taxis, many of whom claim their livelihoods are being threatened by a business that is, as of now, operating illegally.
Thailand is the last country in Asean where hailing a taxi from drivers without commercial licences via mobile apps is illegal, apart from Laos where no such service is available. Despite this legal impediment, Grab has thrived in Thailand but claims its illegal status has stymied its growth.
The company aims to expand into insurance and e-wallets in the second half this year, as well as extending its Grab Food delivery service to 16 more provinces.