Mr Warnick said that “going to the Bar would fulfil a long-held ambition and the timing was right to do it now”.
“It was a difficult decision to leave such an outstanding team of people,” he said in a statement.
“I see this as an opportunity to achieve greater balance personally and to increase my work and lifestyle choices – including the option of doing more pro bono work, especially in the non-profit sector.”
Mr Warnick joined Lavan in June last year, after building a reputation as one of Perth’s top corporate lawyers with national firms Blake Dawson (now Ashurst) and before that Mallesons Stephen Jaques (now King + Wood Mallesons).
His stature was highlighted by his role as a lead adviser to BHP Billiton on its proposed merger and iron ore joint venture with Rio Tinto.
“I think there are more opportunities to make a leadership contribution at a firm that is at an earlier stage of its development, that is smaller, and is based in Perth,” he told WA Business News last year.
“He has brought us the benefit of his many years of experience working for top tier clients across Australia.
“We wish him well and look forward to working with him in a different but similarly rewarding capacity.”