From Sunday, the price of liquefied petroleum gas (LPG) will rise 50 satang per kilogramme every month from 18.13 baht/kg now, until it reaches 24.82 baht/kg in September next year.
The fuel tariff (Ft) rate for electricity will also rise by seven satang per unit.
After the rise, the Ft will be 54 satang per unit, up from the current 46.92 satang.
The Ft is reviewed every four months.
Tolls for urban expressways will also increase by 5-10 baht, depending on vehicle size, starting Sunday.
The Energy Ministry has introduced several measures to ease the impact of the price hikes on low-income earners.
About 7.5 million households across the country which use 90 units of electricity or less each month, as well as those without access to electricity, will be allowed to purchase cooking LPG at the old price of 18.13 baht/kg.
The subsidy will be capped at a maximum of 18kg per three-month period.
Street food vendors and small-scale vendors using 15kg gas cylinders and with vending areas of 50 sq m or less will also be allowed to buy 150kg of LPG per month at the old price.
However, the measures have failed to drown out criticism of the price hikes.
The Democrat Party Saturday slammed the LPG gas price rise, saying it would hit ordinary households hard.
"The cooking gas price for household use should be low. Nobody will say a thing if the LPG price for the petrochemical industry is high, but the government claims that would not be fair for the industry," Democrat spokesman Chavanond Intarakomalyasut said.
"And the government claims the price hike is to curb excessive use. I don't know of any cabinet minister who leaves the gas on when it is not being used. It doesn't make sense."
Mr Chavanond said the price hike shows the government is putting the interests of the industrial sector and PTT Plc ahead of the public.
He said this was particularly disappointing since Prime Minister Yingluck Shinawatra had pledged to rein in the cost of living during her 2011 election campaign.
Mr Chavanond said that by September next year, a 15kg gas cylinder would cost almost 400 baht. The current price is 290-300 baht.
Several food vendors in Klong Toey area said Saturday the LPG price rise would leave them no choice but to charge their customers more.
They said that despite the Energy Ministry's measures to ease the impacts of the hike, not every vendor is eligible to buy LPG at the old price.
Malee, a vendor in Chanthaburi's Muang municipality, said local authorities had asked local food vendors to register for the subsidy. But she had no idea how or when she would receive the money.
A coffee vendor and a food vendor in the same neighbourhood said they would initially bear the extra cost and would not raise prices.
Meanwhile, Internal Trade Department (ITD) chief Wiboonlasana Ruamraksa said the department is taking steps to prevent food vendors exploiting the gas price hike.
She said the cooking gas price increase would have little impact on food prices.
A 15kg cooking gas cylinder can be used to cook about 300 dishes, and a rise of 50 satang per kilogramme would increase the cost of each dish by only a few satang, she said.
The department will conduct random inspections of eateries across the country to prevent vendors from price gouging.
She said officials will also inspect gas-filling shops to make sure they do not cheat buyers.
Ms Wiboonlasana said the department will help alleviate the rising cost of living by promoting the sale of ready-to-eat meals through its Blue Flag economy food shops.<>
The department will also organise more Blue Flag produce markets so the public can buy essentials such as eggs, cooking oil and rice at lower prices, she added.