Newly appointed Revenue Commissioner Ruth Kennedy said that 620,000 individuals and business owners received over €430m in tax refunds last year.
According to preliminary data, a further 400,000 people may be entitled to a refund but they need to finalise their tax affairs, Ms Kennedy said.
Speaking on RTÉ's Today with Claire Byrne, the Commissioner said that Revenue understood that people and businesses can face cashflow difficulties.
The key message to those people is that Revenue has a track record of working with tax payers who engage early when facing difficulty, she said.
She said people or businesses should not let debt build up and urged them to contact Revenue early so that Revenue can spread out their tax liability and arrange to pay it in instalments.
Ms Kennedy said that there were 84,000 entities availing of a debt warehouse scheme and there is €2.8 billion in the warehouse presently.
We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences
Asked how many people pay too much tax, she said that Revenue has real-time information on this.
She said that Revenue has been proactively contacting tax payers, already over 60,000 over the summer, through the MyAccount online service.
Revenue has been writing letters to those who do not use the online service, she added.
Cautioning that scams happen all the time, Ms Kennedy said that Revenue will never send a person a link in an email, and ask someone to fill in a claim form from a link.
It will always be through the MyAccount and there you can see a person's preliminary statement, she said.
The Revenue Commissioner said that last year was a big year for property tax, and it was the first time property owners were asked to revalue properties.
She said that there had been good engagement and Revenue had contacted over 1.4 million in respect of 2 million properties.
Revenue had a 96% payment compliance rate and a 92% return compliance rate as some property owners had paid but had not filed returns.
On evaluations, she said that people are paying in line with expectations and Revenue looks at sales and values, and also has an interactive tool so people can see average property in their area online.
All evaluations are reviewed, as Revenue do spot checks and take a risk check approach using mapping tools and all data available
If someone is selling a property, the tax is reviewed as well, she added.
On shares, Ms Kennedy said employers are using shares as part of an overall remuneration for employees but there are tax implications.
