"I think it's in everybody's interests, it crosses the political divide to see the UK as a place where you can do business."
The Conservatives have used the strike to attack Brown over his party's funding links to the union.
Unite is the main financial backer for Labour, which is trailing the Conservatives in opinion polls before an election expected to be held on May 6.
"His (Brown's) party is a wholly-owned subsidiary of the Unite union," Conservative leader David Cameron told parliament.
"They pick the candidates, they choose the policies, they elect the leader, they have special access to Downing Street. Isn't it true that when the crunch comes he can only act in the union interest, not the national interest?"
(Additional reporting by Caroline Copley, Rosalba O'Brien and Fiona Shaikh; Editing by Charles Dick)