Paul Jones said he felt "hoodwinked" by David Cameron who last year threatened to impose tough new laws on internet giants if they did not take action.
Mr Jones told Channel 5 News that not enough had been done in the fight.
A Downing Street spokesman said there was "always more to do" on the issue.
Coral and Paul Jones from Machynlleth, Powys, launched a high-profile campaign after Mark Bridger, 47, was found guilty of their daughter's abduction and murder last year.
Five-year-old April went missing from outside her home on 1 October 2012. Her body has never been found.
Referring to Mr Cameron, Mr Jones said: "I think he's hoodwinked us a little bit by coming out banging the drums, but hasn't actually put any money in place - he's left it to the internet [companies]."
He added: "When I last met David Cameron I said 'aim high' - but he's fallen well short of the mark."
Last July, the Mr Cameron threatened to impose tough new laws on internet giants if they failed to blacklist key search terms for abuse images.
In November, Google and Microsoft promised to introduce new software that will automatically block 100,000 "unambiguous" search terms which lead to illegal content.
Bridger's trial highlighted the issue of internet abuse after the killer was found to have accessed child abuse images online just hours before April was snatched.
As a result, Mr Cameron agreed to meet April's parents last year to discuss the problem and how to address the issue.
A Downing Street spokesperson said: "The Prime Minister has personally led an effort to eradicate child abuse imagery from the web, which has seen the setting up of a new National Crime Agency, nationwide child-safe internet filters and the first-ever agreement from the main search engines to block illegal images in the last year alone.
"Of course, there is always more to do, and we are continuing to work with other countries, industry and other groups to look at where further action can be taken."
The father of murdered schoolgirl April Jones has accused the Prime Minister of falling "well short of the mark" in a pledge to clamp down on online images of child abuse.