Since the tsunami struck on Boxing Day, the aid agency has spent £5.1m on 33 projects, reaching more than 250,000 people.
Reconstruction projects have included post-traumatic stress counselling, mobile education facilities and helping minority groups gain compensation.
The charity said it has experienced some impediments, such as delays in gaining accreditation as an NGO to work in Sri Lanka. But a spokesman described the problems as "slightly red tape - pink rather than scarlet".
Richard Miller, ActionAid's UK director, said: "Clearly, we would have liked to have spent 100 per cent of the money allocated for the period, but logistical problems have meant that accessing tsunami areas as quickly as we wanted has not been possible. However, we are hopeful that by the first anniversary of the tsunami, in December, we will have achieved our total target expenditure."
ActionAid plans to spend more than £30m over the next three years, in five tsunami-affected countries - India, the Maldives, Somalia, Sri Lanka and Thailand.
Miller added: "As one of the leading aid agencies working on relief and reconstruction programmes in the aftermath of the tsunami, ActionAid has a responsibility to the millions of British people who dug deep into their pockets and gave so generously.
"What we are able to show with these figures is that the money they donated is being spent properly, on time and on budget."
The charity has claimed that its decentralised philosophy is one reason for its effectiveness in responding to the disaster.
Khursid Alam, ActionAid's tsunami programme co-ordinator, said: "We see it as our job not to act as decision-makers for people, but rather to enable them to make important decisions for themselves.
"This could be in the form of funding, expertise or support."