Mining magnate Bridgette Radebe has asked President Jacob Zuma not to sign the Minerals and Petroleum Resources Development Act Amendment Bill into law, she said on Thursday.

Radebe told the Cape Town Press Club the SA Mining Development Association (Samda), of which she is president, made the submission last week.

It gave a presentation during the Mining Sector Stakeholders' Consultative Forum that Zuma chaired.

The technical task team made its submission, followed by input from organised labour and business, including the Chamber of Mines and Samda.

Radebe, also chairwoman of Mmakau Mining, said the submission was in response to the chamber asking Zuma to sign.

"So we said to the president, please president don't sign. So I am not sure what his final decision will be. It is not a decision against the chamber or for or against someone."

Radebe is the older sister of businessman Patrice Motsepe and is married to Justice and Constitutional Minister Jeff Radebe.

She said she may be married to a politician but she was not politically correct. She was passionate about transformation of the mining industry.

She believed there were loopholes in the bill that needed to be closed and other issues that needed to be corrected.

The mining charter had also not yet been aligned with the trade and industry department's BBBEE codes of good practice.

This alignment was overdue in addressing transfer pricing and charter non-compliance by mining stakeholders, she said.

The amendment bill was passed by Parliament before this year's election and sent to Zuma for assent.

At the start of the month, he said he was awaiting a reply from National Assembly Speaker Baleka Mbete before deciding whether to sign the bill into law.

In a written reply to a parliamentary question, Zuma said he had received submissions against signing the bill into law from Legal Resources Centre attorney Henk Smith and Democratic Alliance MP Wilmot James.

"Mr Smith and Dr James have requested that I refer the bill back to the National Assembly... on the grounds that the National Assembly, National Council of Provinces and the provincial legislatures failed to take reasonable steps to facilitate public involvement when the bill was passed."

Zuma said he had written to Mbete seeking her advice on the process that was followed by both the National Assembly and the National Council of Provinces before the bill was passed.

"The information will assist me to take a decision regarding the bill," he said.

Among other things, the bill aims "to provide for the regulation of associated minerals, partitioning of rights and enhanced provisions relating to the regulation of the mining industry through beneficiation of minerals or mineral products".

Economists have warned it could scare off mining investors, and create difficulties for the sector.