British Prime Minister Gordon Brown's office says hosting the London Group of 20 summit is likely to cost around 19 million pounds ($26 million).
The cost includes nearly 6 million pounds to an events management company.
Opposition Conservative Party lawmaker Greg Hands says families struggling with Britain's recession will question the amount being spent on the two-day event.
A spokesman for Brown's office, speaking on condition of anonymity in line with policy, said the cost of the April 2 summit is being kept to a minimum.
He says last year's G-8 summit in Japan cost $285 million, while a 2005 G-8 summit in Scotland cost 80 million pounds.