Under new WA laws anyone who defies an exclusion order could face a maximum $36,000 fine and three years in prison

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Activists and a Greens MP have threatened legal action after the Western Australia police banned at least 12 people entering a designated security area where the Land Forces weapons expo will be held in Perth from 6 October.

The police used special powers given to them by the WA government last month to ban the activists from entering the area surrounding the Perth Convention and Exhibition Centre.