British Prime Minister David Cameron has warned in Britain's parliament that Britain faces troubled economic times, after it voted last week to leave the European Union, but said the government would not abandon its rules on limiting public spending.

"There's no doubt in my mind these are going to be difficult economic times," Cameron told parliament.

"If we do see economic difficulties, one of the ways we have to react to that is to make sure that our public finances and economy remain strong . So I don't think it would be right to suspend the fiscal rules."