Lambert first to bid for Day's seat

Lawyer and Family First parliamentary staffer Rikki Lambert is the first to declare an interest in replacing Senator Bob Day, who has quit parliament because of financial problems with his housing group.

Mr Lambert, who worked as chief of staff in Senator Day's office, says he will be a candidate for the casual vacancy.

"I confirm I will be seeking the Family First Australia nomination to replace Senator Day," Mr Lambert tweeted on Monday.

Other possible candidates include Kenyan-born lawyer Lucy Gichuhi, who was number two on the SA Family First Senate ticket at this year's election.

SA Family First South Australian MP Dennis Hood told reporters the process to replace Senator Day was underway.

It will involve the party's executive nominating a candidate with that person then to be ratified by a joint sitting of both houses of the SA parliament.