Deputies to the National People's Congress had a heated discussion on school bus safety after the issue was written into the 2012 government work report, Xinhua reported Tuesday.

After several school bus accidents in 2011, authorities launched a nationwide overhaul and issued new rules to address the problem. But some deputies from grass-roots units learned that some places simply suspended school bus services, forcing students to take unauthorized buses, known as "black buses".

Deputies discovered that high cost was the main reason for the suspension of school buses.

"Limited finance is the main obstacle schools face," said Li Jianbao, an NPC deputy from Hainan University.

He cited as an example Haikou Huandao Experimental Primary School, which needs over 30 buses to meet demands. That means more than 20 million yuan ($3.17 million) is needed to buy buses, and even more to cover other expenses such as gas and drivers' pay, which is beyond the school's budget capacity.

"Governments at all levels should offer financial support," Li said. "The current governments are totally able to afford it."

Some suggest extending public bus lines to schools as a way to cut the cost of school buses.

But hardware is not enough. "We do not only need school buses to ensure safety, but also need high-standard management, like monitoring and law enforcement," said Zhang Fengbao, a deputy from Tianjin University.

"Regular monitoring systems should be strengthened," said Jiang Jian, another deputy. For example, school bus speed limit should be 10 km/h lower than the standard speed limit, and speeding should be severely punished.