THE Royal Melbourne Show will kick off two days later than usual next year.

The new start date means the show will now encompass the entire school-holiday period, from Saturday, September 18 until Tuesday, September 28.

Previously it had begun on the Thursday before the beginning of the spring school holidays.

Royal Agricultural Society Victoria chief executive Mark O'Sullivan said the move would make the show more accessible to young families.

"The change was made in response to community feedback," Mr O'Sullivan said.

"It provides a greater opportunity to grow the event."

Mr O'Sullivan said it was unlikely the Victorian Government would reinstate the show day public holiday that it revoked 15 years ago.

"The RASV decided to respond to community calls for greater accessibility by moving the entire show calendar to the school holiday period," he said.

Held since 1884, the Royal Melbourne Show is Victoria's most popular annual community event, attracting an average of 500,000 people each year.