The world's biggest security company said that despite global uncertainty, it had recorded a positive start to the year.
Chief executive Ashley Almanza said: "Against a backdrop of macro-economic uncertainty, the group had a positive start to the year.
"We continued to implement our strategy to transform the group's focus and performance and this is reflected in our revenue growth and improving profit and cash generation."
However, G4S took a £1m hit linked to restructuring, and revenues from businesses that are being closed or sold off fell from £218m to £186m.
G4S added that it is managing a number of what it calls "onerous contracts", almost all UK public service contracts, to an effective conclusion.
In March, the firm said that it could take a hit if the government extends a contract to house asylum seekers in Britain.
Mr Almanza is attempting to turn G4S around after a number of public scandals, including a prisoner-tagging contract in 2013 and its botched handling of security at the London Olympics in 2012.
G4S reported a 40% decline in pre-tax profit in 2015, falling to £78m from £128m a year earlier.