Dotcom said the request was made on April 15, 2010, when Mr Banks was preparing to campaign for the Auckland mayoralty.
He said there were at times three other people in the room while the donation was discussed - and Mr Banks rang later to thank him for it.
The allegation comes after police were asked to investigate Mr Banks' listing of a $15,000 donation from SkyCity as "anonymous".
Political candidates are required by law to declare donations if they know who made them. Failure to do so is punishable by up to two years' imprisonment and up to a $10,000 fine.
A vacancy is automatically created if any MP is convicted of an offence punishable by two years or more, no matter what punishment they get.
In the case of Mr Banks, a conviction would place at risk his Epsom seat under the Electoral Act and force a byelection. The loss would leave the Government exposed, with its 59 votes in the 121-seat Parliament supplemented only by United Future's one and the Maori Party's three.