A PROPOSED bid to force private schools to come under majority black control under a much contested empowerment law is illegal, education minister David Coltart said on Wednesday, highlighting divisions within the coalition government over the policy.

A government notice issued last week by empowerment minister Saviour Kasukuwere gave foreign-owned banks and private schools a year to comply with a law requiring 51 percent shareholding by local blacks.

But Minister of Education David Coltart, a member of the Movement for Democratic Change (MDC) party in a coalition government formed with President Robert Mugabe's Zanu PF, said the directive was illegal.

"This action is unlawful, unconstitutional and therefore unenforceable," Coltart said on his official Twitter account.

Coltart also told the state-controlled Herald newspaper on Wednesday that Kasukuwere had previously assured him that private schools would not be targeted under the empowerment drive.

He said most private schools, formerly the preserve of whites but are now largely multi-racial, were owned by churches and trusts.

Prime Minister Morgan Tsvangirai who is sharing power with long-ruling Mugabe in a shaky coalition, has also sharply criticised the empowerment law and said Kasukuwere's latest announcement does not reflect the cabinet's position.

Kasukuwere, a Mugabe ally, has already forced mining companies such as Rio Tinto and Impala Platinum , the world's second-largest platinum miner, to turn over majority stakes in their local units to black Zimbabweans.