A large spillage of chicken offal led to the closure of an Auckland motorway overnight.

Authorities were forced to close off part of the Southern Motorway, between Papakura and Drury interchanges, for some time as they worked to clear the mess.

Police said just after 1am the southbound lanes in that part of the motorway was blocked off and was not expected to open until about 3am.

Police said the source of the spill is not yet known.