Several rockets hit the facility at Sui, 320km southeast of Quetta, capital of Baluchistan province which borders Afghanistan and Iran on Friday night.
Paramilitary forces guarding the key installation responded with rockets and mortars and the exchange of fire lasted for several hours, they said on Saturday.
"We have received reports that a paramilitary sepoy [soldier] was killed in the incident which happened late Friday," provincial home secretary Aftab Jamal said.
Jamal said eight civilians including a girl were also injured in the attack, which briefly disrupted gas supply to southern Sindh province.
The 5,215km Sui pipeline network is a major supplier of domestic gas and has often been attacked by local tribesmen demanding jobs and royalties from the company for the gas coming through their area.
The tribesmen say the natural wealth of Pakistan's most resource-rich province is not trickling down to ordinary people.