Members of the Public Fundraising Regulatory Association are being offered 50 per cent off their membership fee if they also join the Fundraising Standards Board.
The discount will apply when organisations join the PFRA or renew their membership. It has more than 135 members paying either £100 or £250. More than 1,000 charities have joined the FRSB. It needs to increase its membership significantly to achieve financial independence before government funding runs out in 2010.
Mick Aldridge, chief executive of the PFRA, which has a seat on the FRSB board, said it was important for the FRSB to succeed.
Alistair McLean, chief executive of the FRSB, said: "For PFRA members who have not yet joined the FRSB, this offer will be the nudge they need to sign up."