Speaking at the G8 summit, UK Prime Minister Gordon Brown said: "This is the strongest possible statement.
"It shows the unanimity of the whole international community, reflecting the outrage people feel about the violence, the intimidation and the illegitimate holding of power by the Mugabe government."
The BBC's Laura Trevelyan in New York says the US has already tabled a resolution calling for an arms embargo against Zimbabwe, and a travel ban and asset freeze on Mr Mugabe and 11 top Zimbabwean officials.
France's ambassador to the UN has told the BBC he believes those in favour of the resolution have the nine votes out of 15 needed to pass it.
Five nations have the power to block it by voting no, among them China and Russia who, along with South Africa, have reservations about sanctions against Zimbabwe - however, they could abstain, our correspondent adds.
On Monday, Tanzanian President Jakaya Kikwete, who also heads the African Union, said African leaders favoured some sort of power-sharing government.
Isolating and demonising Zimbabwe is not in the best interests of anyone
Bright Matonga Zimbabwe's deputy information minister
Meanwhile, the opposition MDC has denied reports it is ready to resume talks with the government.
The party says 5,000 of its members are missing and more than 100 of its supporters have been murdered since a first round of elections in March.
The Zimbabwean government blames interference from Western countries for delaying a solution to the country's political impasse.
"It is the UK that is pushing for sanctions, but isolating and demonising Zimbabwe is not in the best interests of anyone. They should treat Zimbabwe as a partner rather than an enemy," South Africa's News24 website quotes Zimbabwe's Deputy Information Minister Bright Matonga as saying.
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