Meat, poultry, fish, milk, and yoghurt prices all fell.
"Prices of fruit and vegetables can move more because of changes to supply and demand which can be affected by the growing season and weather," said Food and Grocery Council chief executive Katherine Rich.
"I'm told that crops like avocados can vary from year to year, which affects supply, and that there has been a big growth in the numbers of New Zealanders enjoying them, which means more pressure on demand.
"For many grocery items' prices, there has actually been deflation due to regular promotions and discounts."
The price of fruit and vegetables has increased by 8.9 per cent since April last year, the figures show.
Vegetables rose 6.3 per cent, led by a 69 per cent jump in tomatoes and a 46 per cent increase for cucumbers.
Fruit prices rose 1.1 per cent, led by avocados and strawberries.
"The average price for tomatoes in April 2016 was $6.70 a kilo, up from $4.81 a kilo a year ago," Statistics New Zealand consumer prices manager Matt Haigh said. "Avocado prices more than doubled from April 2015 and were at their highest level since July 2015."
In February, freak storms were blamed for a poor avocado harvest causing shortages nationwide.
Growers predicted an abundant supply again by October but until then consumers were warned they would have to pay top dollar.
Broccoli also experienced a significant price boost. The average price for a kilo was $6.26 last month, compared with $4.81 in April 2015.
Not surprisingly, dairy prices fell. The average price for 500g of butter was $3.65 last month, compared with $4.65 in April last year.
Meat, poultry and fish prices fell 1.7 per cent, beef declined 3.9 and chicken fell 2.3.
Non-alcoholic drinks fell 0.2 per cent in the past month, led down by energy drinks and bottled water.
Restaurant meals and ready-to-eat food rose 0.2 per cent and grocery foods gained 0.1 per cent, as a 4.2 per cent rise in cheese prices was offset by lower prices for lollies.
"Prices of grocery fluctuate throughout the year, in particular products affected by commodity prices such as chocolate and butter and by seasonality such as fruit and vegetables," said Antoinette Laird of Foodstuffs NZ.
"This year was a particularly light year for avocado production. In fact it is the lightest in approximately the last six years.
"On top of this the avocado industry is highly export driven and this year international demand was high.
"All of these factors, of course, have an impact on the price the New Zealand consumer pays."
