Cheras MP Tan Kok Wai said that the "steep" fuel hike and increased electricity tariffs would cause people from all walks of life to be affected.
"We want the Government to announce that the increase will be halted immediately.
"If they don't, it will be a nightmare. The public anger is already at its peak," he told the press Thursday during a peaceful protest at the Pudu market here.
Tan added that if the increments were not halted, it would lead to "runaway inflation".
He also said that the Government was not "leading by example" when asking the public to have a change of lifestyle.
"What does the Prime Minister mean when he tells people to change their lifestyle? Eat less? Spend less?
"But what about the Government which has always been extravagant? What is the Government doing when it asks the people to tighten their belts?" he asked.
He gave the example of a study trip to Europe and Canada organised by the Federal Territory Ministry, Kuala Lumpur City Hall (DBKL) and Putrajaya Corporation, which involves a delegation of 15 high-ranking officers, including FT Minister Datuk Seri Zulhasnan Rafique and KL mayor Datuk Abdul Hakim Borhan.
"When they return on Tuesday, they must explain to the people why the trip had to be made.
"Government officials have made hundreds of trips in the name of studying. So much money has been spent, but where are the improvements?" he said.
Seputeh MP Teresa Kok also questioned why Malaysia's fuel prices had to be so high when we are an oil-exporting country.
"We call for the Petronas account to be made public, since it is a government-owned company.
"We want to know the income and expenditures, and how the Government spends the profits," he said.
The peaceful protest started at about 11am, and was dispersed by 12.30pm by the police. No one was arrested.
Other DAP members there were Bukit Bintang MP Fong Kui Lun, Segambut MP Lim Lip Eng, Teluk Intan MP M. Manogaran and Teratai state assemblyman Jenice Lee.