The theory that Collingwood pair Lachie Keeffe and Josh Thomas could have eaten beef contaminated by clenbuterol in New Zealand has been rejected by the NZ beef industry.

Keeffe and Thomas tested positive to the banned drug several days after returning from a week-long training camp in Queenstown, New Zealand, where they reportedly ate out several times, including a steak meal.

Already sidelined: Collingwood's Lachie Keeffe and Josh Thomas tested positive to a banned substance last year Credit:Justin McManus

Australian cyclist Michael Rogers was cleared after testing positive to clenbuterol in 2013 when authorities accepted he could have eaten contaminated meat while racing in China two months earlier.

While clenbuterol is used in livestock in some countries, New Zealand beef industry association chairman Bill Falconer was adamant that was not the case in his country.