The Morrison government has announced further delays to its $300 million biosecurity levy designed to cover the increasing cost of threats to Australian agriculture and the environment.

The levy was set to begin in July this year and generate $100 million a year to biosecurity funding for three years.

The government has delayed a levy on importers to pay for increased biosecurity protections. Credit:Damian Shaw

But importers criticised the levy design and called for major changes, arguing it would hit the competitiveness of the freight supply chain, key export industries and the cruise sector, as well create higher costs for consumers.

Monday's mid-year economic update revealed plans for the levy to begin this year had been abandoned.