Wesfarmers is offloading another $500 million worth of shares in supermarket Coles.

The Perth conglomerate is selling 28.2 million shares, representing around 2.1 per cent of shares, at $17.75 each. That sits roughly 1.8 per cent under the last traded price of $18.08.

Wesfarmers once held roughly 15 per cent of Coles, but has been selling off its stake in the supermarket since 2018.

Its last selloff was in 2020, when it offloaded 5.2 per cent of shares for $1.1 billion.