A Sydney semi-retired businessman has been charged with attempting to murder his wife by spiking her tea with ant poison, according to court documents.

Stephan Wagner, 61, appeared in Campbelltown Local Court on Wednesday, a day after being arrested at his Lanark Place, St Andrews home.

Police allege his 66-year-old wife, Glenda Wagner, was poisoned and became seriously ill after drinking tea prepared by her husband.

While searching the house, police seized a bottle of insecticide that is being tested.

According to court documents, Wagner is alleged to have poisoned his wife with Ant-Rid, a common domestic pest control product sold in supermarkets.