Fifty jobs out of a total of 175 could go, and the worldwide company is also understood to be considering swingeing cuts in working hours and stopping holiday pay.
The company is based at Kingston industrial estate, where it produces audio and video cables.
Sanmina has been contacted by the Scottish Government's Skills Development Scotland agency, which co-ordinates help for people at risk of or going through redundancy.
It is now waiting on consultations with staff taking place before offering to go in.
Sanmina moved to Port Glasgow several years ago after leaving Spango Valley, where they took over part of the IBM plant.
They manufactured laptop and desktop computers there, but shut up shop in January 2006, sacked 370 people and moved production to Hungary. There is speculation a similar fate could await the Port facility, for the company also has cable production plants in China, Mexico and California.
No one at the Port Glasgow factory is allowed to speak to the media. They referred inquiries to San Jose in California, but no comment was available from there, either.
The company has also refused so far to confirm anything to Inverclyde MP Iain McKenzie, who said today it was probably suffering from severe competition from countries which pay cheaper wages.
He said: "I'm glad to hear Skills Development Scotland are involved.
"Hopefully, everyone will get help to go on to further jobs or re-training."
The MP added: "I'm bitterly disappointed Sanmina have not contacted me. I would like to be given the opportunity to offer assistance, but all they are saying so far is 'no comment'."