Oxfam Great Britain will be suspended in Haiti for two months pending an investigation into sexual misconduct by employees of the aid group, a Haitian government minster said.

Haiti is investigating how Oxfam Great Britain responded to reports that some of its staff used prostitutes while working in the country in the aftermath of the devastating January 2010 earthquake, said Minister of Planning and External Co-operation Aviol Fleurant.

It is also trying to determine whether some of the prostitutes may have been underage.

Authorities consider it a “serious crime” for an adult to have sex with anyone under 18, Mr Fleurant said.

He said the Haitian government is “shocked at the highest level” about reports of misconduct by employees of the organisation.

Oxfam Great Britain is one of four divisions of the international organisation working in Haiti.

The aid group disclosed that seven workers were fired or resigned in 2011 after a whistleblower accused staff members of misconduct while working in the country.

The organisation has admitted that some of its employees used sex workers.

British government officials and the UK charity regulator have said that Oxfam did not tell them the allegations included sexual misconduct until the Times newspaper revealed details of the case earlier this month.

Since then, thousands of people have cancelled donations to the group in anger.

Oxfam International, the umbrella organisation, has apologised to the people of Haiti and said it has created a new plan to improve oversight of its employees.

Oxfam Great Britain contributes about 20% of the budget to the organisation’s overall work in Haiti and the group expects the suspension will have a “significant impact” on its efforts in the country, the group said in a statement following the announcement.

It said senior officials with Oxfam International met with Haitian government officials and committed to co-operate with their investigation.