Robert Mugabe is using the war in Iraq as a "smokescreen" for carrying out human rights abuses in Zimbabwe, the shadow foreign secretary has said.
Campaigners want greater sanctions against Mugabe's regime
Conservative MP Michael Ancram called for ministers to lobby the Commonwealth and the European Union to step up pressure on Zimbabwe's president with tighter sanctions.
His comments follow arrests, and alleged torture, of activists from the opposition Movement for Democratic Change (MDC), after they went on strike last week.
Mr Ancram said the international community must not let the Iraq situation to distract attention from President Mugabe's "campaign of violence".
"Robert Mugabe's cynical use of the war as a smokescreen to execute the most grotesque human rights violations is despicable," he said.
"Ethnic cleansing, genocide, horrific attacks on opponents and a campaign of
violence are all happening whilst the eyes of the world are engaged elsewhere."
Mr Ancram urged the government to "state the case clearly for an immediate
strengthening of sanctions against Mugabe's evil regime by the Commonwealth and the EU".
"Mugabe's ruthless use of violence and intimidation cannot go unreported. Britain must not turn a blind eye to the people of Zimbabwe in their hour of need."
Following last week's strike, hundreds of MDC activists have been arrested and many say they were tortured.
This "unprecedented violence" against political opponents was condemned by the United States.
Following the strike, President Robert Mugabe warned the MDC not to instigate violence, saying: "Those who play with fire will not only be burnt but consumed."
A doctor working in a hospital in the capital, Harare, said more than 250 people have been treated there after being beaten by the security forces; many had broken fingers or toes, some had broken legs.
Two women described how men in military uniforms stripped them, beat them, and used guns to sexually abuse them.
The MDC said children of opposition activists had also been assaulted.
Zimbabwean police said about 400 opposition members had been arrested since last week's strike. But they denied the torture allegations.
Zimbabwe opposition leader Morgan Tsvangirai said on Tuesday that the crisis of governance in the country was deepening.
He called for principled dialogue between his Movement for Democratic Change and the government to prevent anarchy and chaos.
Mr Tsvangirai is facing treason charges for allegedly plotting to assassinate President Robert Mugabe before last year's presidential elections.
Zimbabwe, once a regional breadbasket, now has massive unemployment, long fuel and bread queues and inflation of more than 200%.
Up to half the population, some seven million people, need food aid according to donors.