Zimbabwe's constitutional affairs minister says a referendum on a new constitution has been "tentatively" set for March 16 to be followed by fresh elections later in to end the nation's shaky coalition government.

State radio reported Thursday that Minister Eric Matinenga, an aide of Prime Ministear Morgan Tsvangirai, said President Robert Mugabe is expected to proclaim the date in a government notice on Friday. Voting is scheduled over one day, a departure from the routine two days of polling, the radio said.

Advocacy groups say such a hasty poll prevents adequate voter education on the rewritten constitution.

It was completed on Feb. 6 after three years of disputes, bickering and delays. Democratic reforms to the constitution were a key demand of regional mediators after violent and disputed elections in 2008.