A gas price cut is required for Queensland's Gibson Island fertiliser plant to avoid closure this year, with owner Incitec Pivot urging the re-elected Morrison Government to ensure gas was ''available and affordable'' for Australian manufacturers.

Incitec chief executive Jeanne Johns said a decision was "very close" over whether to close Gibson Island in December, with price the only remaining barrier to signing a new three-year gas supply deal for the plant on Brisbane's outskirts.