The Brighton Pavilion Labour MP, a fierce critic of chugging, has described attempts to regulate street fundraising as "ineffective".
On its launch day in February, he questioned the independence of the board, saying he planned to raise the matter in the Commons.
But after a meeting last week he said he had received assurances that the self- regulatory scheme now had sufficient support to tackle public complaints.
"I'm heartened the board now has more than 400 members, including all the leading charities, and I'm satisfied it isn't dominated by the fundraising trade," he said. "I'm comfortable for now that it is serious about self-regulation."
Lepper has even agreed to help promote the board at an event for MPs in the House of Commons in the autumn.
Jon Scourse, chief executive of the board, said: "David is mainly concerned about face-to-face fundraising, but he's obviously gaining confidence in us."
Last week, Lepper encouraged readers of Brighton's local paper, The Argus, and listeners to BBC Southern Counties radio to complain to the board if they encountered rude chuggers.
Brighton traders have accused chuggers in the south coast city of being rude and obstructing shoppers, causing tension between the Public Fundraising Regulatory Association and the local council.
The PFRA claims to have cut face-to-face fundraising by 50 per cent in the city in the past two years.