The National Assembly's Standing Committee on Wednesday rejected the government's proposed changes to resource consumption taxes, saying the newly suggested rates were much lower than required.
The proposal also failed to present proper scientific arguments and factual grounds for the tax rates, the Finance and Budget Standing Committee said.
Nguyen Van Thuan, chairman of the Law Standing Committee, said the changes were "baseless".
In its proposal, the government said taxes on the exploitation of non-recyclable minerals like gold, bauxite and iron should be increased from July 1, but the committee said the newly proposed rates were still far too low.
The government also proposed increasing tax rates for coal while keeping those for crude oil unchanged, but the National Assembly had said last November that the taxes on crude oil, natural gas and coal gas should be increased, said Uong Chu Luu, vice chairman of the National Assembly.
Crude oil and coal should be taxed higher because they carry high economic values, according to the Finance and Budget Standing Committee.
Thuan, meanwhile, said he thought the government wanted to retain the crude oil tax rate because it had already signed contracts with other countries at current tax rates.
But Luu suggested contracts signed before the Law of Natural Resources Taxes came into effect this July 1 should be left unchanged, and those signed thereafter should be adjusted accordingly.
In another sector, the proposal suggested decreasing tax rates for the exploitation of wood by 5-10 percent from the current 15-35 percent.
Vietnam is trying to limit the large-scale exploitation of forests by encouraging the transfer of forests to people, rather than companies, for exploitation under suitable plans, the government explained.
In addition to the tax discussions, Thuan proposed reviewing over VND25.6 trillion (US$1.3 billion) paid in central budget funds last year as advances for projects that were yet to be approved by the National Assembly.
Last year the budget paid a total of over VND37 trillion ($1.9 billion) in advanced for projects.