A BBC Analysis
Sanctions must be maintained on Zimbabwe to "keep the squeeze" on President Robert Mugabe's inner circle, a British cabinet minister has said.
Africa Minister Lord Malloch-Brown spoke to the BBC from an African Union summit, where leaders have called for the sanctions to be lifted.
This follows Friday's unity government deal between the MDC and Zanu-PF.
Lord Malloch-Brown said Mr Mugabe must show he had changed before Britain gave up "the stick" of targeted sanctions.
He told the BBC's Radio 4 Today programme: "It is 'all in good time' as far as sanctions goes. We need to see real progress and results from this new government."
Speaking from the final day of the AU summit in the Ethiopian capital Addis Ababa, he added:
"There is a misunderstanding of what these sanctions are. They are aimed at the individuals - and the companies supporting these individuals - around Mr Mugabe.
"They are not aimed at the country of Zimbabwe or its people. To keep the squeeze on these people, to make sure they do really share power and perform properly in this new government, we need to keep this lever for a while."
Donors have said they would only provide aid once a unity government is in place.
AU leaders' push for the lifting of travel and financial sanctions against the leadership of Mr Mugabe has not been the only controversial call from the summit.
African heads of state meeting in the Ethiopian capital have also renewed calls for a suspension of moves to indict Sudanese President Omar al-Bashir for alleged war crimes in Darfur.
BBC world affairs correspondent Mark Doyle in Addis Ababa says African leaders tend to look after their own.
He says that while Africa has become much more democratic and open in recent years, when it comes to outsiders criticising individual leaders, the AU tends to close ranks.
Older African leaders remember Mr Mugabe as a hero of the anti-colonial struggle, he says.
And while some ordinary Africans believe any debt owed to liberation fighters does not excuse misrule today, they are not in charge, our correspondent adds.
Under last week's deal, Movement for Democratic Change (MDC) leader Mr Tsvangirai will be sworn in as prime minister on 11 February and Mr Mugabe will stay as president.
A power-sharing accord between the MDC and Mr Mugabe's Zanu-PF was signed last September, but got mired in ever more bitter disputes.
The power-sharing government is intended to ease Zimbabwe's economic meltdown but correspondents say this is largely dependent on the restoration of foreign aid and investment.
Zimbabwe is enduring rampant inflation and an escalating food crisis.
Meanwhile the World Health Organization (WHO) says an outbreak of cholera, fuelled by the collapse of infrastructure, has now infected almost 65,000 people and killed nearly 3,300.