The Labour Party has named frontbench MP Shane Jones as its Maori affairs spokesperson.
Mr Jones replaces long-serving MP Parekura Horomia who died late last month.
He will also be associate food safety spokesperson.
The MP for Te Tai Tonga, Rino Tirikatene, will take over responsibility for Treaty Negotiations.
Mr Shearer said Parekura Horomia had left a huge legacy as MP for Ikaroa-Rawhiti and in his roles as Maori Affairs and Treaty Negotiations spokesperson.
A by-election will be held in Mr Horomia's former seat of Ikaroa-Rawhiti on 29 June.