It is also set to cut the number of weekly discounts and catalogue promotions and increase the number of private or own-label products it sells.

At a briefing for investors yesterday the new boss of Coles' supermarkets, Ian McLeod, said the company was trialling the smaller range to see how shoppers reacted.

The trial of smaller ranges has begun in a limited number of stores in Melbourne and, if successful, will be rolled out nationally.

Mr McLeod said the "early results are encouraging … it shows just how over-ranged we are in certain segments".

He said he was busy trying to improve Coles supermarkets, which had been starved of investment under previous management, by improving the quality of fresh produce and cutting queueing times.

"At the moment there are plenty of reasons why (shoppers) can, and probably should, go somewhere else," Mr McLeod said.

Coles is known to stock a wider range of products than rival Woolworths, but is lagging behind its rival in terms of investment in store renovations and openings.