In a ministerial statement today, William Hague referred to recent events in the Middle East and North Africa, saying the "world has changed" since the settlement was announced in October last year.
The BBC Trust today also announced the reallocation of £9 million worth of existing World Service funding to editorial investment over three years.
In the government's spending review in October last year the World Service's Grant in Aid from the Foreign Office was reduced by 16 per cent, with funding to be taken over by the licence fee from 1 April 2014.
In January this year the World Service announced a series of service closures as a result, the lost of around 650 jobs and more than 30 million listeners for the broadcaster.
Earlier this month BBC Trust chairman Chris Patten vowed to try and protect the World Service from spending cuts.
According to the Trust the additional funding announced today will still mean the BBC will need to reduce spend on the World Service by £42m a year by 2013/14.
But the Trust added that its reallocation of funding, the result of lower-than-expected restructuring costs and pension contributions, will help "mitigate the impact of recent funding cuts".
The additional funding will also mean the Hindi short wave service, Somali service and Arab world services will now be sustained.
The Trust said the funding will also allow a small amount of investment in new activities, in particular on new platforms and in emerging markets. The BBC is said to be currently working on the detail of how this funding will be allocated.
In a ministerial statement today Hague added that MPs had highlighted the impact of the reduction in World Service funding on the BBC Arabic Service in particular.
"It is right that we should look at ways in which we can assist the BBC Arabic Service to continue their valuable work in the region. So I have agreed that we will provide additional funding of £2.2m per annum to enable the World Service to maintain the current level of investment in the BBC Arabic Service.
"This will increase the World Service's funding as a proportion of the FCO's budget to just over 14.5 per cent."
Lord Patten said he was "delighted" they had been able to work with the foreign secretary to direct some more funding to these services.
"The additional money will help protect BBC services in the areas where they are most valued and needed.
"However, it does not mean that we will be able to restore all of what has been lost, and there will still need to be some cuts to the World Service as we have known it.
"We are determined that when we take full responsibility for funding of the World Service after 2014, it will have the priority it deserves."
The Foreign Office said it is also discussing the provision of funding from the Arab Partnership Initiative, for specific projects proposed by the BBC Arabic Service or World Service Trust "that could support the development of the media and wider civic society in the Middle East and North Africa region".
In his statement Hague added that the original settlement "was both fair and proportionate".
But he said he "strongly" welcomed the additional support pledged by the BBC, both previously in relation to the Hindi short wave service and today's announcement.
The National Union of Journalists, which has criticised the level of cuts facing services and staff as a result of the funding reductions, said the additional funding was "an opportunity to undo some of the damage".
"It is vital that money to be made available is now used to restore confidence in the BBC World Service as a world-class public service broadcaster," NUJ broadcasting organiser Sue Harris said in a statement.
"It must be used to ameliorate the impact of the cuts programme rather than ploughed into new ventures".
She added that it is hoped that the BBC will consult fully with trade unions before any further developments occur.
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