An ignition apparatus for igniting a premixed charge in a gaseous-fuelled internal combustion engine comprising: an ignition device (90, 180) associated with a combustion chamber of the internal combustion engine (10, 12, 13, 14); at least one of a dilutant injector (120, 122) for introducing a diluting agent that forms a stratified charge around the ignition device and an enrichment injector for introducing gaseous fuel that forms a stratified charge around the ignition device; and an electronic controller operatively connected with the ignition device and the at least one of the dilutant injector and the enrichment injector and programmed to: selectively actuate the dilutant injector and/or the enrichment injector to introduce the diluting agent and/or the gaseous fuel respectively; and when engine load and engine speed are below a predetermined threshold engine load and speed range or a temperature in the combustion chamber is below a second predetermined threshold when the ignition device is actuated: a) when the ignition device introduces a pilot fuel around the ignition device: actuate the dilutant injector to introduce the stratified charge of the diluting agent; or b) when the ignition device does not affect the global air-fuel equivalence ratio in the combustion chamber prior to ignition: actuate the enrichment injector to introduce the stratified charge of the gaseous fuel to decrease a local air-fuel equivalence ratio in a region of the stratified charge. an ignition device (90, 180) associated with a combustion chamber of the internal combustion engine (10, 12, 13, 14); at least one of a dilutant injector (120, 122) for introducing a diluting agent that forms a stratified charge around the ignition device and an enrichment injector for introducing gaseous fuel that forms a stratified charge around the ignition device; and an electronic controller operatively connected with the ignition device and the at least one of the dilutant injector and the enrichment injector and programmed to: selectively actuate the dilutant injector and/or the enrichment injector to introduce the diluting agent and/or the gaseous fuel respectively; and when engine load and engine speed are below a predetermined threshold engine load and speed range or a temperature in the combustion chamber is below a second predetermined threshold when the ignition device is actuated: a) when the ignition device introduces a pilot fuel around the ignition device: actuate the dilutant injector to introduce the stratified charge of the diluting agent; or b) when the ignition device does not affect the global air-fuel equivalence ratio in the combustion chamber prior to ignition: actuate the enrichment injector to introduce the stratified charge of the gaseous fuel to decrease a local air-fuel equivalence ratio in a region of the stratified charge. a) when the ignition device introduces a pilot fuel around the ignition device: actuate the dilutant injector to introduce the stratified charge of the diluting agent; or b) when the ignition device does not affect the global air-fuel equivalence ratio in the combustion chamber prior to ignition: actuate the enrichment injector to introduce the stratified charge of the gaseous fuel to decrease a local air-fuel equivalence ratio in a region of the stratified charge.