The blast took place in the morning hours near the border crossing of Bazargan. No one was injured in the explosion, Majid Boujarzadeh, spokesman for the Iranian National Gas Company said.
The cause of the blast were not immediately known and Boujarzadeh said it was too early to say if it was due to sabotage.
Boujarzadeh said a group of experts were investigating and that technicians were working to repair the pipeline.
Iran's oil and gas sector has been hit by an increasing number of attacks recently but authorities have provided no explanation for them.
Three explosions hit gas pipelines in April near the holy city of Qom in central Iran, temporarily cutting the flow of gas from Iran's gas refineries in the south to the country's northwest.
Similar explosions rocked the pipeline in the same area in February. Officials at the time said the blasts were not caused by technical failures but did not say if they were acts of sabotage.