New Pattaya mayor Sontaya Kunplome started work on Friday and announced policies to the Pattaya Council while critic Veera Somkwamkid complained strongly about conflict of interest.
Mr Sontaya arrived at Pattaya City Hall in the morning and signed an order to appoint four deputy mayors. Later he attended a meeting of the council.
He told members that he would turn Pattaya into the centre of the government's Eastern Economic Corridor (EEC) which covers Chon Buri, Chachoengsao and Rayong provinces, with developments that focus on the economic, social, environmental and cultural aspects of Pattaya.
Mr Sontaya also pledged to improve the environment in the busy beach rsort city by developing facilities to turn garbage into energy.
Garbage disposal in Pattaya was the very issue that critic Veera raised against the new mayor, who was appointed by Prime Minister Prayut Chan-o-cha.
Mr Veera said Mr Sontaya's father, Somchai Khunpleum, had yet to pay about 100 million baht in compensation to Pattaya City in relation to a garbage dump site deal with the city.
Somchai was found guilty in 2005 of engineering the transformation of a forest reserve in tambon Khao Mai Kaew of Chon Buri into a private land plot that was sold to Pattaya City for 93 million baht to be used as a landfill site. He was the mayor of tambon Saensuk in Chon Buri at the time.
Somchai, the longtime local godfather known as "Kamnan Poh", was also convicted in an unrelated case of arranging for the murder of a rival and sentenced to 25 years in jail. He was released last year on grounds of ill health and age.
Mr Veera said the Pattaya mayor was duty-bound to support the confiscation of Somchai's assets to pay the compensation.
He rejected the government's claim that Mr Sontaya would support the implementation of the EEC project. Mr Sontaya was appointed in the lead-up to the next general election and people believe the appointment was part of a political deal, Mr Veera said.
Mr Sontaya is the leader of the Phalang Chon Party and his family has wielded considerable political power in Chon Buri for many years.