The series creator and writer David Sale, stated she was the first major bitch on television, long before Alexis Carrington (Joan Collins)[2] Welch was born Auckland, New Zealand.

Welch appeared as the enchantress Morgan le Fey in J. C. Williamson's production of Camelot in the early 1960s, a role she played for two and a half years.

After that show's writer David Sale, who had earlier been impressed by the performance she gave in the Australian Broadcasting Corporation-Artransa Films science fiction children's series Phoenix 5 (1970), saw her in the relatively minor role in The Group, he promised to write something especially for her next time.

Welch says she partly based her characterisation of Maggie on the Mrs Robinson character played by Anne Bancroft in feature film The Graduate.

After Number 96 Welch continued to make guest appearances in Australian television series, including roles in Glenview High (1977), The Outsiders (1977), Young Ramsay (1978), and in legal drama Case for the Defence (1978).