Aldi

is continuing to dramatically outperform its rivals in the Irish grocery sector and has seen its sales in the Republic

jump by more than 20 per cent over the last 12 weeks, according to retail figure published yesterday.

The increase recorded by retail analysts Kantar Worldpanel comes in spite of a decline in overall sales across the supermarket sector.

The German discounter's overall share of the market rose by 1.3 per cent to 7.2 per cent while its main rival in the own-brand sector, Lidl, also saw its share increase from 5.8 per cent to 6.6 per cent.

The big loser appears to be Tesco. While it remains the largest player in the Republic's grocery sector it saw its market share fall again over the last 12 weeks. It now has 26 per cent of the market compared with 27.7 per cent 12 months ago and a share of close to 29 per cent at its most dominant in 2012.

Dunnes Stores also saw its market share decline over recent weeks. It fell by 1.9 per cent to 23.8 per cent. Along with Aldi and Lidl, SuperValu was the only retailer to show sales increasing and its share of the market is now put at 20.1 per cent compared with 19.9 per cent in the same period last year. It is likely to see a bigger increase in market share over the course of 2014 after it rebranded all 24 Superquinn shops under its own brand last week in a move which will bring in about 30,000 new customers.

Appearing in the rankings for the final time, Superquinn recorded a decline in market share from 6.5 per cent to 5.1 per cent over the 12 week period. The business unit director at Kantar Worldpanel Mark Thomson said the slowdown in supermarket spending was partly linked to price inflation.

"The fall in prices across vegetables is still a contributing factor to the performance of the grocery market, with shoppers spending €12 less on fresh vegetables compared with the same period last year. Although levels of inflation are reducing in Ireland, the financial pressure on people's budgets remains an important factor in deciding where people shop, and what they are buying," he said.