German police have ramped up security ahead of Munich's Oktoberfest beer festival following a series of terror attacks.

For the first time in its 200 year history the festival will be fenced in, with twice as many security staff to patrol the festival, and an additional 100 police officers present, dpa reported.

The festival. which attracts around six million people annually, begins on Friday 16 September and lasts for 17 days.

The security boost comes after a 17-after-old Afghan refugee injured several people in a knife and axe attack in a train near Wurzburg, Bavaria, on 18 July.

Days later an 18-year-old Iranian-German killed nine people before turning the gun on himself in a shooting spree in Munich, while that weekend a 27-year-old Syrian refugee launched a suicide bomb attack in the town of Ansbach, injuring 12.

Munich's police chief, Werner Feiler, said that there was "no indication of a concrete danger" at the festival. "Go out, have a good time, celebrate – but please pay attention to the normal rules," he said.

Large big bags and rucksacks will be prohibited in the festival, and there will be increased security checks at perimeters. Festival security will be able to dismantle the fence in less than a minute in case of an emergency.

The festival has been targeted by terrorists before, with a right wing extremist killing 12 and wounding 200 in a bomb attack in 1980.