Cape Town - Former Proteas coach Mickey Arthur has warned that Australian quickie Mitchell Johnson could pose South Africa some problems on their upcoming tour.The Australians are set to tour South Africa in October and November and Arthur believes South Africa is just the right place for Johnson to find form again.The left-handed fast bowler has come under fire recently for some indifferent performances for the Baggy Greens and will be determined to perform against the Proteas. He was Australia's star performer with 16 wickets in three Tests on their previous tour to South Africa at the start of 2009 - when they avenged their home Test series loss to the South Africans a few months earlier.And Arthur believes the South African conditions will suit Johnson."He really enjoys bowling in South Africa," Arthur told the Volksblad newspaper.Bowling mentor Troy Cooley, who was on Monday appointed as Australia's interim head coach for the tour to South Africa, also feels the conditions will suit Johnson."I think the conditions there (South Africa) suit the fast bowlers and the places where we will play (Cape Town and Johannesburg), will suit them (the fast bowlers)," said Cooley.Arthur - who currently coaches Western Australia - also singled out batsman Shaun Marsh as a potential threat to the Proteas. Marsh recently scored 141 on his Test debut against Sri Lanka.Arthur says current New South Wales Blues quickie Patrick Cummins - who might be considered for the tour - is another dangerous player.Australia will announce their squad for the tour to South Africa later this week.