The online vaccination portal opened at 7.30 am and will close at 8pm on Monday for people aged 43 and 44.
Vaccination appointments for Pfizer, Moderna, Astrazeneca and Janssen jabs are now made available.
Last week, the Health Ministry included the Janssen vaccine for the first time following re-evaluation by the European Medicines Agency.
Both Janssen and the AZ vaccine have been probed following links to very rare blood clots.
In a bid to speed up its vaccination coverage to 65% of the population with at least one dose of a COVID-19 vaccine, GPs can now give people over 30 the AstraZeneca jab.
The Health Ministry also said it would provide GPs, who express an interest, with quantities of the AZ vaccine.
As of last Friday, a total of 236,265 vaccinations (26.8 doses per 100 inhabitants) were carried out, of which 176,082 (20%) concerned the administration of the 1st dose and 60,183 (6.8%) concerned the administration of both doses.