By Richard Black
Environment correspondent, BBC News website
The agreement commits governments to providing good gorilla habitat
Countries that are home to gorillas have pledged to monitor how laws against harming the animals are being implemented on the ground.
Most gorilla range states have laws against poaching, but environment groups say enforcement is often lax.
The agreement came on the final day of discussions in Rome on an international gorilla action plan that came into force earlier this year.
With most populations falling, the UN has made 2009 the Year of the Gorilla.
This week's talks, held during the UN Convention on Migratory Species (CMS) meeting, were aimed at turning the intentions of the action plan into firm measures.
"Virtually all of the 10 gorilla range states have laws against poaching," said WWF International's species programme manager Wendy Elliott, who is at the Rome meeting.
"But are poachers arrested, are they taken to court, are they put in jail?
"The law is not always an effective deterrent."
Germany and Monaco are among countries that pledged new money at the CMS conference to support the action plan.
Some of it will be used to train the judiciary, with the intention of improving implementation of existing laws.
The gorilla action plan is designed to tackle the three main threats facing gorillas - loss of habitat, poaching and the Ebola virus - and all the 10 range states have signed up.
The plan commits them to securing good habitat for the animals, including the creation of reserves that cross national boundaries where that is appropriate.
They are supposed to clamp down on poaching and reduce the impact of conflict.
There was some good news this week from Virunga National Park in the Democratic Republic of Congo, where rangers were able to return to the area where mountain gorillas roam, after having been forced away by armed men a few weeks ago.
Tackling Ebola is likely to be a harder task. So far, there is no effective treatment or vaccine for the virus in humans or in other primates.
The factors that make gorilla populations more or less vulnerable are also not understood, although fragmenting forests into small areas may be a factor, possibly because it increases contact and therefore transmission of the virus between gorillas and humans.
The Year of the Gorilla (YoG) campaign is spearheaded by a number of top experts including Jane Goodall, the renowned biologist and conservationist.
Another of the YoG ambassadors, Ian Redmond of the Great Apes Survival Partnership (Grasp), said that in the long run, looking after gorillas can be very beneficial for local communities.
"In Rwanda and Uganda, tourism, with gorillas as the star attraction, has become the number one foreign exchange earner," he said.
Their role as "gardeners of the forest" was also vital to the long term ecological health of Africa's tropical rainforest, he added.