Stormont's Deputy First Minister claimed the administrations in Washington and Dublin were also of the view that London should make a contribution in the event of an agreement on how to deal with the contentious issues of flags, parades and the legacy of the past.
Northern Ireland Secretary Theresa Villiers said the Government could not guarantee additional support but said any bid would be considered "very seriously".
Stormont is currently locked in political impasse on a draft deal to resolve the three divisive issues. Former US diplomat Dr Richard Haass, who chaired a six-month talks process in a bid to find agreement, has proposed a blueprint settlement that has yet to achieve consensus.
The leaders of the five parties, Sinn Fein, SDLP, DUP, UUP and Alliance, are due to meet again today in a bid to make progress.
Mr McGuinness told the Assembly the onus was on the British Government to contribute financially to implementation. "I think there is a huge responsibility on the British Government in particular to recognise that in the event of agreement being reached that they should make a financial contribution," he said.