Foreign firms have until September 25 to present their plans to government on how they will comply with the law that requires them to sell 51% stakes to locals.
Zimplats is among 11 firms that were given ultimatums in August to furnish "acceptable" indigenisation plans.
"Zimplats continues to defy the laws of this land," Indigenisation Minister Saviour Kasukuwere was quoted as saying by the state-run Herald newspaper on Wednesday.
"We have taken the position to deem them non-compliant in terms of provisions of the Indigenisation Act," he added. Kasukuwere will now contact the mines ministry "with a view to initiate the process to revoke the operating licence of Zimplats", the paper said.
Impala Platinum of South Africa has the majority shareholding in Zimplats, which mines for platinum on the Great Dyke, a range of hills stretching through central Zimbabwe.
Mugabe insisted that foreign investments in the county would be safe, if they met the new requirements.
"As the implementation of the indigenisation and empowerment policy continues to gather momentum, government looks forward to full cooperation by all stakeholders to achieve a win-win outcome," Mugabe said as he opened a new session of Parliament.
"I wish to assure investors that their investments in the country remain safe and urge them to comply with the country's laws."
Mines and banks are the main target of the law, but Finance Minister Tendai Biti said two weeks ago that the rules could be relaxed for banks.
Kasukuwere has also issued an ultimatum to financial services provider Old Mutual, allegedly because it had "failed" to implement an earlier empowerment proposal.
"You are required to provide me with the progress report within seven days of receipt of this letter, failure of which no further indulgence shall be granted", he said in a letter dated September 1.
Law will discourage investment
The equity law is strongly supported by 87-year-old Mugabe but has created tensions within Zimbabwe's rocky unity government, with Prime Minister Morgan Tsvangirai arguing that it will discourage investment.
The new session of Parliament is expected to debate a new law governing diamond mines. Exports of the gems have been restricted since 2009 over concerns about rights abuses in diamond fields.
Lawmakers also must approve a law to govern the holding of a referendum on a new constitution, a key step toward new elections under Zimbabwe's three-year-old unity accord.
Mugabe, whose Zanu-PF party was blamed for most of the deadly violence that undermined Zimbabwe's last elections in 2008, called for peace as the country moves toward new polls.
"As we forge ahead, let us continue to exert our energy in fostering unity, peace, development and equality of opportunity of all our people," he said.
"Let us therefore in unison say no to violence in all its manifestations."
Mugabe has already been endorsed as his party's candidate in the new elections, likely to again pit him against Tsvangirai in polls expected next year. - AFP, Sapa-DPA