Professor Luke O'Neill says the Government should be 'banging down doors' to boost vaccine supply here.
The leading immunologist says Ireland should be going 'wherever the vaccine is available', including buying the vaccines being produced in China and Russia.
He's also calling for borders to be 'tightened up' ahead of current restrictions being eased.
When it comes to vaccine rollout in Ireland, recent weeks have seen a number of delivery shortfalls from manufacturers - most recently AstraZeneca.
The HSE is confident it will hit future targets, after missing two weeks in a row as a result of shortfall.
However, Professor O'Neill told The Pat Kenny Show the Government should now be looking everywhere for vaccine supplies.
He said: “I’d be banging down the doors - this is the most important thing to get right in the coming 3-4 months.
"If supply is an issue, any Government should be looking to boost supply in whatever way they can.
"It isn't against the rules of the European Union to go to a company directly and try to get extra supplies off them.
“If I was the Taoiseach, I’d be sending the troops to bang on the doors of all the companies now."
Professor O'Neill last week spoke about how Russia's Sputnik V vaccine has been shown to be safe, and should be approved for use in the EU.
However, he said two Chinese-produced vaccines are 'also looking great' and are being used very widely.
He argued: "You could see us getting some of those, potentially, into the country.
"I’d be seriously looking at ways of getting more vaccine supplies in.
“I’d go wherever the vaccine is available.”
Over the weekend, President Higgins signed into law the legislation necessary for 14-day mandatory hotel quarantine.
It will initially apply to people arriving from 33 'high-risk' countries.
It's expected to be in effect by next week, but the Government is still finalising a contract with a service provider.
Professor O'Neill says it's vital border controls are in place.
He said: "We’ve got to tighten up the borders, especially as we open up.
“When we go to a situation where the virus is extremely low in Ireland, the risk comes with travel.
"We’ve got to be extra-zealous then in the coming months with regards to travel.”
Mandatory quarantine will apply to arrivals from Angola, Argentina, Austria, Bolivia, Botswana, Brazil, Burundi, Cape Verde, Chile, Colombia, Democratic Republic of the Congo, Ecuador, Eswatini, French Guiana, Guyana, Lesotho, Malawi, Mauritius, Mozambique, Namibia, Panama, Paraguay, Peru, Republic of South Africa, Rwanda, Seychelles, Suriname, Tanzania, United Arab Emirates, Uruguay, Venezuela, Zambia and Zimbabwe.