The delivery firm is removing commission completely on collection orders and waiving sign-up fees for new operators joining its platform, but only until 19 April.
It is also relaxing rules to allow restaurants to work with other delivery aggregators such as Deliveroo and UberEats, regardless of contractual terms.
While the measures are initially only for 30 days, Just Eat says it will review the situation and support package "as the crisis continues to develop".
“These are some of the most challenging times the restaurants we work with have ever been through,” says Andrew Kenny, UK managing director at Just Eat.
“We know our restaurant partners are worried about their teams - from chefs to delivery drivers - and these measures will go some way to helping them maintain their operations and support their people."
Just Eat has 35,700 restaurant partners and delivers to 95% of UK postcodes.
It is also working on unspecified initiatives to support vulnerable and isolated people, front line workers and its couriers, which will be announced in due course.
The Government is set to relax rules to allow restaurants to operate as hot food takeaways without the need for planning permission.