As the Western Cape surpasses the one-million mark in its vaccination drive, the provincial health department has cautioned residents that the supply of vaccines could throttle the number of doses being administered this week.

The Western Cape health department said the addition of new age groups to the vaccination programme had caused a surge in demand for jabs.

"We have seen enormous excitement and eagerness for people to get vaccinated. We appreciate the uptake of registration and vaccination. We have seen, as new age bands are added, that this causes excitement and increased demand for vaccination, which is a positive sign," the department said in a statement.

However, the demand has also placed pressure on the vaccine supply. The province has received 96 000 vaccine doses for public sites this week. This must also cover the vaccination of those needing their second doses.

"This week, our demand for vaccination temporarily outstrips our vaccine capacity at many sites, but we want to assure everyone who has registered that they will be vaccinated in due course," the department said.

The department is currently administering around 150 000 vaccine doses a week.

On Tuesday, the Western Cape became the third province to pass the one-million mark in Covid-19 vaccinations.

Earlier this week, Aspen made available the first tranche of Johnson & Johnson (J&J) vaccine doses packaged at its Gqeberha plant. Aspen did not say how many doses were being released, but last week the health department said it was expecting to receive 1.4-million doses from J&J this week.

"We do anticipate more vaccines being made available to provinces in order for us to vaccinate even more people and have been assured that the general supply of vaccines shows a positive increase from next week," the health department said.