Johannesburg - Finance Minister Nhlanhla Nene should have announced bolder steps to reduce government spending in his budget on Wednesday, Cope said.
"Minister Nene should have taken the bull by the horns and demanded a decrease in the size of the government and a substantial reduction in consumption side expenditure," Congress of the People leader Mosiuoa Lekota said in a statement.
"He shied away from this," said Lekota.
Nene announced that consolidated government spending was expected to be R1.35trn, and revenue about R1.2tn.
Lekota said national debt in 2018 would be at around R2.3tn, which was unsustainable.
He said Nene had raised concerns that substantial repayment of debt was coming due, but made no mention of where this money would come from.
"How is this going to be paid?" Lekota asked.
"In the past few years short-term debts were being converted by the government to long-term debt. Is he going to persist with that practice and encumber our youth to settle these debts in the future?"
Cope supported Nene in implementing new requirements for the Auditor General to furnish compliance reports, and welcomed the move to give additional funding to the Public Protector's office.
Cope believed the creation of a single supplier database interfaced with the SA Revenue Service and the payroll was another progressive step.
"If municipalities follow the SARS model for electronic payments, all sides will be well served," Lekota said.
Nene announced some personal income tax increases, a hike in the general fuel levy, in the Road Accident Fund levy and in the electricity levy, and increased excise duties.
READ: Some taxes, fuel, electricity levies to rise
"Though the tax increases are progressive and not aggressive this year, the country is being readied for what is to follow in future years," said Lekota.