Zimbabwe's state-run press is floating the possibility that Robert Mugabe will annul last month's presidential election and call for a national unity government with himself as president while a new constitution is negotiated and a fresh ballot held.

The proposal, in an opinion piece in the Herald, is not a formal Zanu-PF plan. But the newspaper is often used by the ruling party to lay the ground for policy changes. The proposal is viewed by the opposition as another attempt by Mugabe to overturn the election results.

Yesterday, Gordon Brown repeated British accusations that Mugabe was trying to rig the elections. The prime minister said he would propose an embargo on all arms going to Zimbabwe.

With the results of the ballot still unannounced 25 days after it was held, and a partial recount of parliamentary and presidential votes taking days, it is increasingly apparent that the Zimbabwean government is undecided on the way forward.

Zanu-PF has touted the idea of a presidential run-off with the opposition Movement for Democratic Change's candidate, Morgan Tsvangirai. But despite the ruling party's campaign of violence against opposition voters, Mugabe can be far from certain of winning, particularly with growing regional scrutiny. His government appears to be stalling while it finds a credible way to hold on to power.

In the Herald article, Obediah Mukura Mazombwe, a pro-Zanu-PF academic, wrote: "The [ruling] party should allow MDC-Tsvangirai, now in virtual exile, to return home and freely negotiate its participation in a [Southern African Development Community-mediated] process that should lead to the establishment of a transitional government of national unity led by the incumbent president."

He also suggested fresh elections after a referendum on the constitution.

Tsvangirai said he would accept a power-sharing government if he is installed as president and Mugabe retires.