Local authorities should lift restrictions on out-of-hours supermarket deliveries to help the environment, a government report has recommended.

The report, by Defra's Food Industry Sustain­ability Strategy Champions' Group on Food Transport, conceded that restrictions on evening and night deliveries were designed to protect residents' interests. But it said this meant delivery vehicles were forced onto the roads at peak times, adding to congestion and more fuel consumption.

The number of restrictions had grown to the point that more than half of one major supermarket's stores were subject to restrictions on out-of-hours deliveries.

"This is a significant issue requiring close consultation with local authorities, but removing these restrictions would have a significant impact on the environmental impact of food transport," said the report.

A spokesman for Asda, whose chief operating officer David Cheesewright chaired the Champions' Group on Food Transport, said one of its stores in Manchester was not allowed to receive deliveries after 5pm on a Saturday or at all on a Sunday. This meant stocks were low on a Monday morning.

"Many restrictions are historic, based on original planning permission for the store or when lorries were noisier," said the spokesman. "If deliveries have to happen between 9am and 5pm, then lorries sit in traffic, increasing congestion."

The report said it had identified possible changes to current industry practices that would reduce the social and environmental costs of domestic food transport by 20% by 2012.

The report also recommended consumers should shop for groceries online. "Having your weekly grocery order delivered through one of the many home shopping offers may feel extravagant but benefits the environment as one van trip replaces many individual car trips to carry the same amount of product."

Half the total environmental impact of food transport is caused by individual consumer shopping trips, the report added.

Defra will launch a consultation next week to canvas opinion on how the proposals can be taken forward.