Fatal NSW explosion re-investigated

An explosion that killed a man outside a home in the NSW Central Tablelands a year ago remains a mystery.

John Burrows, 58, was killed by an improvised explosive device as he walked towards his mother's garage in the tiny village of Portland on July 24 last year.

Police have will resume searching surrounding bushland for remaining fragments of the IED, including a metal plate.

"If you have any information about why Mr Burrows was targeted, or can assist with information about any pieces believed to form part of the IED, then please come forward," detective inspector Colin Cracknell said on Sunday.