Another person has been infected with measles during an outbreak in western Sydney, with NSW Health urging people to be alert for symptoms.

The man spent time in the Blue Mountains, Strathfield and Leichhardt while infectious before presenting to hospital on Good Friday, NSW Health said in a statement.

The victim, who contracted the disease in Quakers Hill, was isolated and is recovering well.

“This brings us to 22 cases of measles in NSW residents with onset in 2017,” communicable diseases director Dr Vicky Sheppeard said in a statement on Monday.