It was Sunday, when one never shouuld, but Melina Mercouri was out campaigning last weekend in the Piraeus district she has represented as an opposition Socialist member of parliament since 1977.

The fiery actress, whose "Never on Sunday" role as a big-hearted prostitute on the Piraeus dockside gained her international recognition, is running in the Oct. 18 parliamentary election on a Panhellenic Socialist Movement ticket for the Piraeus second district.

She is referred to by everyone as "Melina" and wryly described by one opponent this way: "She is to Greek politics as champagne is to a dinner -- not strictly necessary but certainly adds a dash of glamor to the proceedings." Mercouri's formidable personality and the appeal she holds for women voters clearly make clear an asset for the opposition.

"My constituency is the constituency of the littly guy," said Mercouri, 54, who in 1977 was elected on a feminist platform by an overwhelmingly female vote, as she spoke in her chic Athens penthouse apartment before setting off for Piraeus. "It is a microsm of Greece. The problems of people there are those of the entire country -- too few schools, too few hospitals, inadequate housing, transport and sewerage, pollution."

On the way the volatile actress, who said she works "from eight in the morning to midnight," commuting between Athens and her constituency office, chewed mints to calm her nervousness, speculated anxiously about the size of the waiting crowd and fretted over the cost of running an election campaign.

Once there, however, Mercouri rose to the occasion, addressing with tough camaraderie a crowd gathered in the middle of an illegally unit hillside shanty town in the dockyard suburb of Perama.

"You've got problems and I know about them," the avowedly Marxist Mercouri told the crowd, to enthusiastic shouts of "You're our Melina."

"The government of the right has encouraged you to come here because it wants cheap labor, but it has not provided housing for you so you are forced by the state to live illegally. I am here to make a pact of honor with you that [the Panhellenic Socialist Movement] comes to power your problems will have top priority," she said.

Making a special ptich to the women in the crowd, most of whom wore aprons and had several children in tow, Mercouri said that "the government treats most working people as second-class citizens, but women as third class. We will set up a special body responsible for women's affairs, to make sure you get your rights."

"It's my birthday on Oct. 18, so I hope you will vote for me," Mercouri, clad in blue jeans, joked as she left amidst a flurry of kisses and embraces. "I am a woman of a certain age you know, and I would like to celebrate the occasion."

Along the narrow store-fronted streets of the central Piraeus area of Nikaea, a trail of victory-sign posters led to Mercouri's office on the coffee shop-lined main square.

"The people of my district know me and trust me. There is not idolatry between them and me -- I am not a Taylor," Mercouri said as she strode across the square, chatting and returning greetings of "Hi, Melina."

"My grandfather was an Athens mayor and my father was also a leftist deputy in parliament. In my family I learned to be laiki , a woman of the people. So my people here know I will help with their problems and that I won't let them down."

Mercouri said she does not rule out the possibility of a Cabinet post after the elections, in the event of a Socialist government. "The Ministry of Culture has been mentioned, also perhaps a new ministry for women's affairs," she said. "But it is up to the party to decide."

Mercouri, who said she has turned down an offer to make a film with Italian feminist director Lina Wertmuller, because of the demands of the election campaign, said she sees no problem in being both an artist and a political figure.

"Artists and politicians have this in common: they both must understand and communicate with people," she said.

"I see no contradiction or conflict between the two professions," she added, settling down to a game of coffee-shop backgammon with an elderly constituent. Anyway, today we have a mediocre actor as president of the United States."