JOHANNESBURG, OCT. 31 -- The South African government said today it is deporting a British woman for throwing a tomato at President Pieter W. Botha yesterday during a bravery awards ceremony in Pretoria.

According to local press reports, the woman, Sally Joanna Hutchings, plucked a tomato from a buffet table during the ceremony and hurled it in the direction of Botha and his wife, Elize, missing both.

Hutchings was identified as a lecturer at Pretoria's University of South Africa, where the incident occurred. University spokesmen said that before the bravery awards function, Hutchings had given notice that she was quitting her post and was expected to leave South Africa to return to Britain in November.

In a statement today, F.W. de Klerk, acting home affairs minister, said that Hutchings had "hurled an object" at the president, without identifying it as a tomato.

"This action, although without serious injurious consequences and itself not perilous, is considered in a very serious light. Should the object have contained explosives, the lives of the state president and other persons could have been in jeopardy," de Klerk said.

The government did not say when Hutchings, who was arrested by security police immediately after the incident, would be deported.