Australian cricket coach Darren Lehmann is reportedly set to resign in the next 24 hours.

The Australian mentor, who has overseen World Cup triumphs and Ashes series sweeps, is set to become the first casualty of the ball tampering crisis which threatens to tear Aussie cricket apart.

The 48-year-old was under mounting pressure to walk away after a series of cricketing greats labelled his position as head coach untenable — despite Cricket Australia's integrity unit yet to finalise its investigation into the scandal.

London's Telegraph reports Lehmann will stand down in the next 24 hours and informed Cricket Australia chief executive James Sutherland of his decision on Monday (AEDT).

The report claims Lehmann's decision is the reason Sutherland finally decided to travel to South Africa on Monday.

It follows reports Western Australia coach Justin Langer has already been sounded out by Cricket Australia to step in as interim coach for the Fourth Test in Johannesburg beginning Friday.

The Telegraph also reports that Smith and Warner are facing the prospect of 12-month suspensions.