Corporal Roberts and Private Silibaravi were attached to 1st Battalion The Royal Welsh Battlegroup, and were serving as part of Combined Force Burma, when they were killed in an indirect fire attack on Forward Operating Base Ouellette, in the northern part of Nahr-e Saraj district.
The children of a soldier Cpl Roberts have paid a touching tribute to their father saying: "We wish yesterday had never happened."
Friends and relatives hailed their bravery as bosses said they "undoubtedly" saved the lives of both Afghans and fellow servicemen.
Corporal Roberts, who was born in Middlesbrough, was on his second tour of Afghanistan and had served on operations in Bosnia and Iraq.
Cpl Roberts was the Section Commander in 23 Pioneer Regiment The Royal Logistic Corps and was responsible for leading a team trying to detect Improvised Explosive Devices in high risk areas.
The Ministry of Defence has said the he not only facilitated freedom of movement for International Security Assistance Forces and Afghan National Security Forces, but also undoubtedly saved the lives of both Afghans and International personnel.
Besides his girlfriend and children, he also leaves behind his parents, Pauline and Stephen, and his brothers and sisters, Tracey, Mark, Darren, Michael and Emma.
He was praised by colleagues as a "talented Junior Non Commissioned Officer" with a "cheeky grin" who was "one of their finest" of his squadron.
His colleague Fiji-born Private Silibaravi, also 32, was commended as a "quiet, yet determined and popular soldier".The serviceman, who leaves behind his parents, Meli and Merewalesi, his brother Saimoni, and sister Mereoni, was new to the specialist role of Advanced Searcher. His job also involved working to detect make-shift bombs.
Private Silibaravi - known as Sili or Prince - was described as a "soldier's soldier" and praised for his "quiet confidence" and "clear inner strength".
Private Silibaravi, a keen sportsman, joined the Army in 2002 and served in Iraq and Afghanistan. This was his third tour of duty.
He represented the Regiment at both athletics and rugby.
A total of 412 members of UK forces have died since operations in Afghanistan began in October 2001.